Hunt Institute for Botanical Documentation

The Torner Collection images are in the public domain and can be downloaded from the Torner Collection of Sessé and Mociño Biological Illustrations database. When using these images, please include the following credit statement: Torner Collection of Sessé and Mociño Biological Illustrations, courtesy of the Hunt Institute for Botanical Documentation, Carnegie Mellon University, Pittsburgh, Pa. The artworks also are available for on-site viewing by researchers; please contact the Art Department for additional information or to arrange a visit.

Other resources

For thumbnails of the Torner images, see the Catalogue of the Botanical Art Collection at the Hunt Institute database. To locate these images in the database, search on "Sessé and Mociño" in the artist's name field. Erased information is indicated by {}. Information on zoological subjects can be located in the Description field (try Aves, Osteichthyes, etc.).

For information about portraits of and biographical citations for Sessé and Mociño, see the Hunt Institute Archives Register of Botanical Biography and Iconography database.

Historical introduction

by Rogers McVaugh (1909–2009), recognized authority on the Sessé and Mociño Expedition, from the now out-of-print The Torner Collection of Sessé & Mociño Biological Illustrations CD-ROM (1998)

The watercolor drawings in the Torner Collection constitute a resource unique in the history of systematic biology. Having survived the vicissitudes of almost two centuries, including 160 years of obscurity when they were lost to science, these illustrations are now available for consultation and study. Almost half of the approximately 1,800 botanical paintings are of primary importance to students of tropical American plants because they have been used as the bases of names applied by botanists to species new to science. The precise identities of such species, and consequently the modern applications of the names, are often impossible to ascertain from published descriptions alone, without study of the paintings on which the descriptions depend. These important considerations aside, the paintings are valuable sources of information about the distribution of weeds and of cultivated plants in tropical America in the eighteenth century, about plant distribution in areas now obliterated by urban development or by agriculture, and about artistic techniques and the development of individual artists under the conditions imposed by working in rude surroundings in the midst of an exploring expedition traveling by mule train.

The history of the paintings (except for the long hiatus when no botanist knew where they were) is well documented and full of extraordinary circumstances and coincidences. That they should have survived in essentially perfect condition, without fading or mildewing, is a minor miracle. Almost all of them were painted between 1787 and 1799, during a series of long excursions in rural Mexico, in Cuba and Puerto Rico, in Central America, and along the Pacific Coast as far north as southern Alaska. They were assembled and sent back to Spain in 1803 as part of the study material for producing a Flora Mexicana. They remained safe in Madrid during the political uncertainty of the Napoleonic period. When the French left Madrid in 1812, the paintings were hand-carried (in a cart, as the story goes) in the wake of the retreating army into France. In Montpellier and later in Geneva they were subjected to intensive botanical study from 1813 to 1817. Duplicates were culled from the collection, and eventually about 1,200 of the other paintings were parceled out to 120 persons in Geneva, that they might be copied quickly before the originals were returned to Spain. The collection reassembled, it was returned to Montpellier, to the hands of the one surviving botanist of the American expedition, who tarried a while with it in southern France, then finally reached Barcelona, where he died, alone and impoverished, in 1820. The paintings then disappeared from public view. It has been supposed that they remained in the possession of the doctor who had attended the botanist during his last illness, and indeed in 1898 a Mexican scientist, searching for the paintings, found a grandson of that same doctor, who remembered the collection but had no knowledge of its whereabouts. No one knows how, or exactly when, but sometime before 1900 the paintings became part of a private library in Barcelona, where they remained almost unnoticed because the owner's primary interest was in non-biological subjects and where they survived the Spanish Civil War buried in a cellar. In 1979 the then owners of the library surmised the scientific value of the paintings and sought to arrange for their permanent preservation and accessibility for study. Thus, the collection emerged unscathed, and came eventually to the Hunt Institute.

Background

The Torner Collection paintings were part of the documentation of the work of an expedition to New Spain authorized in 1786 by Carlos III of Spain to survey the "natural productions" of that part of his domain, and to establish there a botanical garden. This has been called "The Royal Scientific Expedition to New Spain," "The Natural History Expedition" (since it included zoologists as well as botanists), or, by botanists, "The Sessé and Mociño Expedition" (after the two best-known botanists who participated in it). By contemporaries, including the writer of the Royal resolution of 27 October 1786 that authorized the expedition, it was always spoken of as "la Expedición Botánica."

An extensive literature on the Botanical Expedition has grown up since 1926, apparently stimulated by the completion about that time of the listing in Index Kewensis of the many new plant names published between 1887 and 1894 in the posthumous volumes attributed to Sessé and Mociño. Martín de Sessé y Lacasta (1751–1808), a Spaniard, conceived the idea of the expedition and acted as its administrative head during the whole period it was active in America. José Mariano Mociño (1757–1820), Mexican-born of Spanish descent, joined the expedition in 1790 and forged ahead rapidly as the most active and productive botanist associated with Sessé in the work on the new Flora Mexicana. He traveled widely, and kept most of the records of what the group accomplished. He returned to Spain with Sessé in 1803, and after Sessé's death it was Mociño who tried to keep the project alive.

For political and other reasons, the great flora was never published (and indeed never completed), but the manuscript bases for it remained in Madrid. In 1870, the Sociedad de Historia Natural de México learned of the existence of these manuscripts, and after extended negotiations published some of them, in two works attributed to Sessé and Mociño, a century after their preparation and long after both style and content had become obsolete. The volume called Plantae Novae Hispaniae (1887–1891; ed. 2, 1893) is a real flora, prepared as a unit, and intended to name and describe the Mexican plants studied by the expedition during their first three years in the field, up to about April of 1791. The volume miscalled Flora Mexicana (1891–1897; ed. 2, 1894) is in no sense a unit. It treats a miscellany of species from all parts of America visited by the expedition, including at least 450 already included in Plantae Novae Hispaniae. It may be characterized as a collection of notes and manuscripts that had been kept together with the idea of one day organizing them into a definitive flora (McVaugh 1977).

These posthumous publications, obsolete and nomenclaturally troublesome as they may be, nevertheless include more than 1,000 newly proposed species, carefully and reasonably well described, and with names validly published. They cannot be ignored, but identification of the new species described in them often poses problems. Most of the new names, naturally enough, fell into synonymy because the same species had been given other names by other authors during the century the manuscripts lay unpublished. Some few of Sessé and Mociño's species, however, have proven to have no earlier names. It is this need for careful identification of the names published in Plantae Novae Hispaniae and Flora Mexicana that has stimulated much of the recent interest in the Expedición Botánica.

The Work of the Botanists and Artists of the Botanical Expedition

From the beginning of the expedition it was planned to include artists as an integral part of the group (McVaugh 1977, 1980). As soon as possible after the formal incorporation on 4 August 1787, the Director (Sessé) appointed two young Mexican artists who had been recommended to him by the Director of the Royal Art Academy of San Carlos in Mexico. Atanasio Echeverría y Godoy, less than 18 years old when he joined the expedition, was thought (and proved) to be the more talented, but the other, Juan de Dios Vicente de la Cerda, eventually developed into a draftsman and colorist of more than average ability. Arias (1968, 44–45, 76–77) described the two as "jovencitos, dóciles y vivísimos en el trabajo." Most of the paintings in the Torner Collection seem to have been made by one or the other of these two, though only one (422) was signed by Echeverría (and that with the date 1805, after the expedition had returned to Spain); Cerda signed 1436 and 1638, and 1928 bears details and notes in his handwriting; three of the illustrations (415, 419, 1718) are signed by Pedro Oliver, an artist who seems not to have been mentioned in the accounts of the expedition. Probably Cerda's first trial paintings under the directions of the naturalists were made in October 1787 in the vicinity of Mexico City, and those by Echeverría soon thereafter. By the beginning of May 1788, the two artists had already finished about 187 plates. From then until the virtual cessation of botanical activity about ten years later, one or both of them accompanied each major field excursion to make paintings of plants and animals. Wilson (Mociño 1970, lviii) says that another artist, Francisco Lindo, "worked with the Royal Scientific Expedition in New Spain," but I have not seen his name mentioned elsewhere.

The members of the expedition thought of their work in terms of "excursions," some of which lasted as long as two years. The "First Excursion," which lasted from August 1787 through the year 1788, was hardly an excursion in the modern sense. The group moved from one temporary base to another, exploring the Valley of Mexico and the surrounding mountains, undertaking trips to Toluca, Yecapixtla, and, by way of Amecameca, to the tierra templada. Both Echeverría and Cerda took part in this work, though not always together.

Both artists were members of the "Second Excursion," to Guerrero (March to December 1789). During this trip the botanists collected material of about 372 new or otherwise interesting species, and the artists completed about 180 paintings.

The "Third Excursion," a trip to the Pacific Coast that lasted from May 1790 until early in 1792, also included both artists. Echeverría and Cerda were both in Tepic on 15 February 1792, after which the former accompanied Mociño on a trip to the Northwest Coast, while Cerda returned to Mexico with Sessé and later that same year went with him first for some weeks to the State of Mexico, then to the Atlantic slope for the rest of the autumn. During the Third Excursion the botanists were becoming more selective and were not finding as many species new to them; they assembled herbarium collections to the number of 172, and the artists finished slightly more than 100 paintings (McVaugh 1977).

From the very beginning of the expedition, a numbered series of Icones Florae Mexicanae was envisioned, to accompany the projected flora. As often neither artists nor botanists knew the identity of a plant that was being painted, the paintings were customarily assigned serial numbers in the order in which they were finished. Only after the completion of the work of the first field season did it seem desirable to make a new arrangement of the paintings on systematic principles (that is, according to the Linnaean system), and to assign new numbers to them. Remnants of the earliest numbering systems, and apparently of some later ones, may be seen on many of the paintings in the Torner Collection, but those systems are imperfectly understood, and few inferences can be drawn from those numbers when they appear (McVaugh 1980). One system, however, runs through numbers 1–460, applied to the Icones made during the first three years of the expedition. Most of these numbers were cited, often with very specific localities indicating the sources of the species, in Plantae Novae Hispaniae or Flora Mexicana, or both.

Mociño seems to have been responsible, at least after 1789, for the assignment of numbers to the paintings. In devising an arrangement for the inclusive Icones, he seems to have left unchanged the numbers initially assigned (presumably by Sessé) to the first 187 paintings, and to have added numbers for the paintings made during the next two years (i.e., about 180 from the summer of 1789 and about 100 from the trip of 1790–1791). The final numbering seems to have been done hastily, under the pressure of finishing the manuscript of Plantae Novae Hispaniae in Guadalajara in the summer of 1791, so that the whole, including more than 100 duplicate paintings, could be returned to the Viceroy in Mexico City (and eventually to the Crown), as evidence of accomplishment before the expedition went on westward.

At least during the first three years of the expedition, and at times thereafter, one or more duplicates of each painting were made in the field at the same time as the original, or somewhat later after the field parties had returned to base. There are many references in the notes and letters of Sessé and Mociño and others to this work of making duplicates of paintings already executed. Sometimes the duplicates were exact copies; sometimes extra flower parts or fruits or dissections of them were sketched in, or more rarely major changes were made in what are still clearly duplicate illustrations. Presumably the original paintings, and the duplicates, were kept together in some kind of order until the expedition returned to Spain. There seems to have been no general record preserved; we do not know how many original paintings were made, or how many duplicates. The extra copies seem to have been made for distribution, not merely as safeguards against the loss of the originals.

One set of paintings must have been kept complete for reference and eventual publication. It seems likely that during the early years of the expedition (1787–1791) two duplicates were often made. For example, during the Third Excursion (1790–1791) the artists completed about 100 illustrations on the journey between Mexico and Guadalajara. On 22 July 1791, Sessé forwarded to the Viceroy, from Guadalajara, the two manuscript volumes of Plantae Novae Hispaniae, and a number of duplicate paintings. He asked that Vicente Cervantes, Professor of Botany at the Botanical Garden in Mexico, be allowed to keep a set of the duplicates, while a second set was to be forwarded to Spain for Royal approval. There seems to be no record of the fate of the set retained by Cervantes, but the approximately 110 duplicates in the other set eventually reached Spain and are still preserved at the Jardín Botánico in Madrid. Long after the expedition returned to Spain, when Mociño was associated with the Swiss botanist A. P. de Candolle, he presented to the latter a set said to have consisted of 309 duplicates. About two-thirds of these represent paintings made during the First and Second Excursions (i.e., from 1787 to 1789), but there are very few or no duplicates from the Third Excursion in de Candolle's collection, now in the Conservatoire Botanique, Geneva. I infer that all or most of the duplicates from that excursion had been distributed in 1791, one set intended for Cervantes, a second for the Crown, and the originals kept for reference.

Indeed it transpires that not all the paintings from the Third Excursion are represented in the Torner Collection, or at least not all have been identified. Fewer than half of the Icones in this portion of the series (394–460) have been found, whereas almost three-fourths of them are represented in the set at Madrid. The same subseries includes depictions of 32 species described as new by Sessé and Mociño, of which only about two-thirds have been identified in the Torner Collection.

Those who are looking for individual Icones in the Torner Collection may eventually find most of them, but there are many inconsistencies and gaps in labeling and numbering, these often making positive identification difficult. The series that is easiest to identify, because most of the plates are named and labeled, is that from the Second Excursion (190–392). Of the approximately 82 new species in this subseries, all but five are in the Collection. There are many gaps in the subseries made in 1790–1791, and as many or more in that made in 1787–1788 (1–187). Out of the approximately 74 new species in the latter, only about 56 are identifiable in the Torner Collection. My surmise is that before Mociño joined the Expedición Botánica the numbering and labeling of the paintings was a somewhat informal affair. As noted above, he seems to have assumed the responsibility for this soon after the year 1789; in the archives at the Madrid Botanical Garden there are lists in Mociño's writing in which he enumerated all the Icones from the different excursions, those in the set sent to Madrid in 1791, and the complete series from beginning to end (McVaugh 1977, 1980). Once established, the routine of numbering and labeling seems to have run smoothly until the expedition set out for the West in 1790, after which the pressure to produce the manuscript of Plantae Novae Hispaniae began to build up during the long Third Excursion, until efficient naming and labeling of illustrations (and perhaps counting of duplicates) began to suffer.

Relatively few duplicates are known from the later years of the expedition, when field parties generally included but one botanist and one artist, and after the system of numbering the Icones was discontinued in 1791. The one major exception seems to have been with respect to the relatively few paintings made by Echeverría during his trip to Nutka (or Nootka) Island in the summer of 1792 (McVaugh 1977; Engstrand 1981). Mociño, the principal naturalist on this trip, implied that Echeverría made at least preliminary sketches of 200 species of plants and some animals, but only about 20 of the botanical sketches are known. Supposedly because of lack of time, most of those known are only partially colored. Apparently they were still unfinished when Sessé and Echeverría went to Cuba in 1795, and were carried along with a view to their completion, as Sessé wrote to the Viceroy in March 1796 that Echeverría had been sick and had not worked on the drawings from Nutka (McVaugh 1977). Wilson (Mociño 1970, xlviii) states that when Echeverría returned from Nutka in 1793, he "apparently placed his original sketches in the hands of fellow artists at the Academy of San Carlos for multiple reproduction"; she lists 16 artists including Cerda and Francisco Lindo who were engaged in this activity. Certainly some copies were made. The original incomplete sketches in the Torner Collection (e.g., 1555, 1948, 1949, 1952, 1953, 1955–1959, 1961, 1964–1968, 1970, 1971, and perhaps 1872 and 1954) are excellent examples of Echeverría's delicate technique. Many of the same sketches (either original duplicates or copies made in Geneva in 1817) are in the de Candolle collection in Geneva. Five of the same drawings, completed in full color but evidently not by Echeverría, are reproduced by Arias (1968) and by Wilson (Mociño 1970) from the Archivo del Ministerio de Asuntos Exteriores, Madrid.

The Attribution of Individual Paintings

Because so few of the paintings are signed, it is not always possible to determine the name of the artist in a particular instance. It is always necessary to consider the possibility that the painting in question may be a duplicate, made by someone other than Cerda or Echeverría, from their original sketches. There may be some such duplicates in the Torner Collection. There are, for example, approximately 45 numbers of the Icones Florae Mexicanae that are represented in the Collection by two (or rarely three) paintings that are essentially identical or at least quite surely are based on the same original. As far as can be ascertained from the numbers alone, more than 30 of these can be dated from the Second Excursion (1789), and the remainder from some earlier year (McVaugh 1980). Aside from these, there is little duplication within the Torner Collection.

Duplication aside, it is possible to make some informed guesses at the authorship of many of the paintings. Echeverría eventually developed a precision of line and shading, and a clarity of coloring, that is immediately recognizable. In some of his work beginning with the Nutka expedition of 1792, details are often improved by viewing under a lens. Almost all the paintings made between 1787 and 1791, when Cerda and Echeverría were both accompanying the field parties in central and southwestern Mexico, seem to have been made in accordance with a predetermined formal style. Usually a rectangular frame was marked out, and the plant drawn to fit the frame regardless of its original size or shape. Most of the numbered Icones were stylized in this way, and it is usually impossible to attribute them to one artist or another.

One small group of paintings, evidently dating from the very earliest days of the expedition, pretty surely represents Cerda's earliest work. The drawings are not included in frames and the sheets are numbered in ink at upper left ("Numo. 2" to "Numo. 9," inclusive). Two of these (1436, 1638) are signed on the back by the artist. The others are 111, 114, 527, 553, 737, and 1002.

After the Third Excursion broke up in the latter part of 1791, Cerda and Echeverría were never in the field together for any length of time. For the next seven years the work of the expedition was carried on by individual botanists going their own ways, each accompanied by one artist, as summarized in the following table (McVaugh 1977):

Dates	Botanists	Localities	Artists
1792	Mociño, Maldonado	Nutka expedition	Echeverría
Jul–Dec 1792	Sessé, Castillo	Mexico (Mexico, Hidalgo, Puebla, Veracruz)	Cerda
Jul–Dec 1793	Sessé	Mexico (Puebla, Veracruz)	Echeverría (? until Aug), Cerda (? later)
Jul 1793–Dec 1794	Mociño	Mexico (Veracruz, Oaxaca, Tabasco)	Echeverría (? after Aug 1793)
Jun 1795–Dec 1798	Mociño	Mexico (Oaxaca, Chiapas), Central America	Cerda
Apr 1795–Mar 1798	Sessé	Cuba, Puerto Rico	Echeverría

Theoretically it should be possible from the above to identify the artist who was responsible for any given painting if one knows the geographical origin of the specimen depicted, except for plants from the Atlantic slope of Mexico in Puebla, Veracruz, and Oaxaca. In practice this is not always feasible, as no geographical information appears on the paintings themselves, and although some species are confined to one region or another, very many of those in the tropical lowlands of the Caribbean basin are widely distributed, and a painting of one of them gives no clue as to whether the specimen depicted came from Veracruz or from Nicaragua. Still, for many of the Torner paintings, it should be possible to link them to more or less specific localities within the limited ranges occupied by the species that they represent, once these have been identified.

Two series of paintings can readily be recognized as regional, both the work of Echeverría. One, already mentioned, is the small set dating from the Nutka expedition of 1792. The plants depicted, with the exception of a few southern Californian species (presumably painted near Monterey, where the expedition paused on its return trip), are characteristic of the humid coastal regions of the Pacific Northwest. Doubtless some or most of them were painted near Nutka, where the expedition spent most of the summer. Some of these paintings were later the bases for newly proposed species named with the epithet nutkana(-us) (e.g., 1966, Rubus nutkanus). De Candolle, when studying Mociño's set of the paintings (i.e., what is now the Torner Collection), presumably had Mociño's advice as to the source of these particular sketches, and at least 14 of them he annotated with the word "Notka" or the added epithet notkana or notkanus. It should be noted as a caveat that at least one of the species, Polygala nutkana (represented by 1947), though published under that name, seems not to have been painted by Echeverría nor to have come from Nutka. Specialists on the genus Polygala have suggested that it was of Mexican origin (Blake 1916). Here, as elsewhere in the Collection, there is the potential for misinterpretation because of the lack of organization and annotation at the time the paintings were made. I cannot explain why formal numbering (and naming) of the Icones seems to have ceased after the field season of 1791. It may have been simply that neither Sessé nor Mociño, constantly involved with the practical details of long field excursions, could take the time to keep lists of what they obtained unless pressure was applied, as it had been in 1791, to make a good impression on their sponsors.

A second regional series includes about 140 paintings that are mostly of West Indian plants. Most of these are on thin watermarked paper, drawn within large frames (ca. 20 × 31 cm). Representative as they are of Echeverría's mature work, they are botanically and artistically among the best in the entire collection. The details shown in some of them are incredibly fine, and the colors, including the yellows, are very vivid. Some of these may represent plants from the Atlantic slope of Mexico, where Echeverría painted in 1793–1794, but most of those that have been identified are West Indian in origin. De Candolle knew that some of the plants represented in Mociño's collection had come from Central America and elsewhere, but seems to have assumed that the species depicted were Mexican unless another origin was stipulated. For example, he described Mouriria mexicana (A. P. de Candolle 1828, 8) from one of the above paintings, assuming that it was based on a Mexican plant, whereas more recent students have agreed that it represents a well-known Puerto Rican species, and surely was painted in Puerto Rico by Echeverría, in 1796 or 1797 (1405).

After one learns to recognize the primarily West Indian series just described, the Nutka set, the relatively crude drawings made in the early days of the expedition, and the 400 or more (perhaps as many as 500) that constitute the Icones Florae Mexicanae, there remains a large group, somewhat more than half of all the botanical paintings in the Collection, that will require prolonged study of the plants and their geographical ranges before it can be subdivided. Probably some of the paintings were made on the Atlantic slope of Mexico, where Cerda spent nine or ten months in 1792 and 1793, and four months in 1795, and where Echeverría spent perhaps as much as a year in 1793–1794. Possibly even more came from the three-year expedition to Central America, when Mociño and Cerda traveled from Oaxaca to the Gulf of Nicoya and returned; they stopped for days or weeks at a number of different localities, including the vicinity of Tehuantepec (Oaxaca), Ciudad Real (i.e., San Cristóbal de las Casas, Chiapas), Guatemala City and the mountains of northern Guatemala, near San Salvador and other localities in El Salvador, and near León and other localities in Nicaragua. They apparently reached León in May 1797, 15 or 16 months after leaving the City of Oaxaca. The return journey occupied an entire year, 1798. The longest stopover was at Ciudad Real, where Mociño stayed almost six months, having asked and been granted permission to stay and put his medical skill at the service of the community, which was having an outbreak of leprosy.

Some of the Torner paintings can be identified with fair certainty as from the Central American trip. For example, 729 represents Jatropha podagrica, a plant known to be native only in Guatemala and Honduras; 691 is annotated "Indigofera guatimalensis"; 746 is Werneria mociniana, named in honor of Mociño (A. P. de Candolle 1838, 324) and said to have come from the mountains of Guatemala; 1456 is Couroupita nicaraguensis (A. P. de Candolle 1828, 294). Doubtless various others from Central America will come to light. Much of the Torner Collection remains to be identified in modern terms, though botanical names were often added to the plates by de Candolle or by others in the nineteenth century. Relatively few names were provided by Sessé or by Mociño.

The de Candolle Collection and its Relationship to the Torner Collection

Several references have been made above to the de Candolle collection in Geneva, and to Mociño's connection with de Candolle. In order to place the Torner Collection in proper perspective, it is necessary to describe in detail the circumstances surrounding the formation of de Candolle's collection, and the scientific importance that it came to have after the disappearance of Mociño's paintings.

It may be argued that Augustin Pyramus de Candolle (1778–1841), a Swiss botanist, was the greatest systematist of his time. He came of a prominent family long established in Geneva, where he was born. He lived and worked for some years in Paris, where he built a solid reputation with his Mémoires on succulent plants (beginning in 1799), on Astragalus, and on other plant groups. He was co-author in 1805, with Lamarck, of a new edition of the classic Flore Française, first published in 1779. He was offered the chair of botany at Montpellier (replacing P. M. A. Broussonet, the late Professor of Botany and director of the botanical garden, who had died in 1807), and moved there in 1808 with his wife and small son (Alphonse Louis Pierre Pyramus de Candolle, 1806–1893, of whom more later). In characteristic fashion he continued to write, publishing early in 1813 a descriptive catalogue of the plants of the botanical garden in Montpellier, and later that year his classic Théorie Élémentaire de la Botanique, which came to have a profound influence on botanical thought in the nineteenth century.

About the time that Mociño, exiled from Spain, arrived in Montpellier with his precious paintings, in 1812 or 1813, de Candolle was already beginning to contemplate, as he said, "une immense entreprise," namely the preparation of a general enumeration of the plants of the world, for which his Théorie Élémentaire would serve as a preface (A. P. de Candolle 1862, 221). This enterprise culminated, of course, in his Systema (1817–1821) and Prodromus (1824–1873), the works for which he is today universally known among botanists. When de Candolle first saw Mociño's paintings, however, his intention had been to work with Mociño on the then little-known flora of Mexico. Finding that most of the manuscripts, aside from the paintings, had been destroyed or lost during Mociño's flight from Spain, he abandoned this idea, especially since early in 1816 began to appear the monumental Nova Genera et Species by Humboldt, Bonpland, and Kunth, a work that he knew at once would cover much of the same ground (and cover it better). He did, however, secure from Mociño permission to copy some of the paintings that seemed to represent new genera or species, and eventually to publish these.

The staff artist at Montpellier, Toussaint François Node-Véran (1773–1852), copied several of Mociño's paintings, and plates based on them soon began to appear in publications by de Candolle and his associates, notably his colleague at Montpellier Félix Dunal, whose monograph on the Annonaceae appeared in 1817, and his pupil L. T. F. Colladon (1792–1862), whose monograph on Cassia was published in Montpellier in 1816. Dunal had already (3 September 1814) published several new species of Solanum with descriptions based wholly upon Mociño's paintings; these appeared in the third volume of Poiret's Supplement to Lamarck's Encyclopédie Methodique. Dunal's descriptions commonly were accompanied by a few words of acknowledgment, for example, "Moz. & Sessé, Plant. Mex. tab. pict." Evidently he had begun to study the paintings in Mociño's collection soon after they reached Montpellier, and almost at once prepared descriptions of what he took to be new species. Additional plates, presumably made at the same time by Node-Véran, are often cited by number in Dunal's later works on Solanum, but have never been published, and have not yet been compared with the presumed originals in the Torner Collection. De Candolle himself, as will appear later, utilized several of Node-Veran's copies in his own publications on Dilleniaceae, Cactaceae, and Theaceae, among others. It is probable that these copies were also made during the time that de Candolle was in Montpellier.

In 1814, after Geneva had become independent of France, de Candolle began to think of returning to the city of his birth, partly because he preferred to have his son educated there. He managed to secure an appointment there as Professor of Natural History, resigned his position in Montpellier, and finally left for Geneva about the end of August 1816. He recorded that he took with him the paintings, and what few descriptions had been salvaged from those done for the Flora Mexicana. Mociño, whom he described as homesick, old (he was about 59), and almost blind, confided the entire collection of paintings to him, saying "Allez, je vous confie le soin de ma gloire!" (A. P. de Candolle 1862, 221).

There are numerous references in the botanical literature to de Candolle's work on the Mociño paintings in Geneva. As a matter of fact, the collection remained in that city only about eight months, during which time de Candolle was partly occupied by a new course of instruction. Previously the collection had been with him in Montpellier for more than three years. When the course was nearing its end, apparently in early April 1817, de Candolle received a letter from Mociño (who had remained in Montpellier), asking for prompt return of the paintings. He had received permission to return to Spain and hoped to leave soon, but dared not return without the pictures, which in his opinion belonged to the Crown. De Candolle, knowing that he must leave for Montpellier with the paintings in about 10 days, reviewed the entire collection and sorted out those of animals and those that he supposed to represent well known plants. The ones remaining, all of which he supposed to be of some botanical interest, were copied (to the number of 1,200 by his count) in ten days by about 120 persons, many of them society women, friends of friends, some of them unknown to de Candolle except for their willingness to help. When the work was completed, de Candolle went at once to Montpellier and returned the original collection to Mociño about 1 May 1817. Mociño at some time presented de Candolle with about 309 of the original duplicate paintings, but whether at this time or before is not known to me. Many, perhaps most, of the duplicates are from the early years of the Botanical Expedition (1787–1791), the period when the Icones Florae Mexicanae were being numbered.

If there are paintings missing either from the Torner Collection or from that at Geneva, it may well be that they were lost or misplaced during the ten days devoted to the copying, when the confusion must have been enormous. De Candolle said, perhaps with not much exaggeration, that the whole city was occupied with the task. He himself spent the time going from one atelier to another, showing the artists how best to make shortcuts or instructing them as to the faithful copying of necessary botanical details. On one occasion a plate was lost in the street from a bundle being carried from one place to another. It was found by an English woman who had heard about the project, made a copy of the painting, and returned it with the original, at the same time offering to do more. De Candolle hastened to send her six more but in his hurry directed them to the wrong person, who in her turn copied them, giving de Candolle the opportunity to send another six to the original discoverer of the lost painting! (A. P. de Candolle 1862, 289).

Fortunately there is a good contemporary record of the entire collection that remained in Geneva. As noted in de Candolle's Mémoires (1862, 290), he prepared a prefatory statement about the collection and the incident of the copyists, then a list of all the paintings in his collection, by number and names by which the plants were known to him or under which they were received from Mociño, with an index to all the copyists and to which paintings were copied by each. He arranged the paintings in numerical order in 13 looseleaf folio volumes (in which they still exist), as he said, in remembrance of the debt that he owed to the goodwill of his fellow citizens.

Now it must be reiterated that Mociño's paintings disappeared from the world of botany in May 1817, and did not reappear until they came to Pittsburgh in 1981. To all intents and purposes the collection of copies and duplicates at Geneva became the source of all knowledge about the paintings of the Botanical Expedition. De Candolle and his contemporaries continued to refer to the expedition, and to publish new species and genera based entirely on the unpublished illustrations, which they cited in various ways in the Latin texts, commonly by abbreviated references (e.g., "fl. mex. ic. ined.," or sometimes "ic. pict. mexic." or "Moz. & Sessé, plant. mex. tab. pict."). Seldom did they make any specific reference to the location of these illustrations; gradually it came to be assumed that all such references were to the collection in Geneva. Between 1817 and 1852, in the two volumes of de Candolle's Systema and in the first 13 volumes of the Prodromus, the names of about 300 new species were based wholly or primarily upon the paintings, and more or less incidental references were made to them in the publication of many other new species. Almost all the new species seem to have owed their recognition and eventual publication to the genius of A. P. de Candolle, though some few were published after his death by A. de Candolle, Dunal, and others. Of the names based on the Sessé and Mociño illustrations, by far the most were published in the earlier volumes of the Prodromus, that is, about 85 in Volume 1 (1824), about 70 in Volume 2 (1825), about 25 in Volume 3 (1828), and successively fewer in the later volumes.

Alphonse de Candolle, 30 years after the death of his father, became concerned about the difficulty, then becoming increasingly apparent, of identifying, from the written descriptions alone, the species that were published in these early volumes and based solely on the paintings. He pointed out that these novelties described in a few words only, had become "une source regrettable de méprises et d'incertitudes." He went on to say that he himself had never used this source of new species except on occasion, when he consulted one of the originals (not a copy), and even then only when the characters were clearly shown. He mentioned several instances of names published unnecessarily by botanists who had not seen the paintings and had misinterpreted the written descriptions. He conceived the idea of distributing a number of sets of high-quality tracings made from the paintings that had served as the bases for these old names. To this end he reviewed the collection thoroughly in 1873 (noting that more than 50 paintings were missing from the numbered series). He selected to the number of 279 the paintings which, in his words, had served as the types of species in the Systema or the Prodromus (A. de Candolle 1874). He offered sets of tracings, somewhat retouched, at cost to the directors of ten of the principal museums of the world, and had no difficulty in disposing of them. He did not have tracings made from paintings that he knew had already been published. The short printed text that accompanied the tracings included a list of the names arranged according to the sequence numbers in the de Candolle collection, with indications of the nature of each painting (that is, as to whether it was an original painting, a colored copy made from an original, or merely a tracing or line drawing made from the original). The sets of these Calques de Dessins went initially to nine botanical museums in Europe—Berlin, Brussels, Copenhagen, Florence, Kew, Leiden, Paris, St. Petersburg, Vienna—and to one in America—Harvard, where the botanical celebrity of the period was Alphonse de Candolle's friend Asa Gray. Additional sets of the tracings, and tracings made from tracings, have subsequently found their way into various other major herbaria and libraries.

One effect of the publication of the Calques was to direct attention to the paintings in Geneva, and to encourage the inference that the new names in question were based primarily upon them. The type concept now current in plant nomenclature was but imperfectly developed in 1874, and the word "type" is not emphasized in the text of the Calques, except that it appears in the heading, "Dessins ... qui ont servi de types d'espéces," and is used at least twice to state that certain paintings are the "types of genera." According to the International Code of Botanical Nomenclature (Greuter et al. 1994), a holotype of a name "is the one specimen or illustration used by the author or designated by the author as the nomenclatural type." When the author of the name uses two or more specimens or "other elements" in preparing to publish the name, and does not designate one as holotype, then one may be chosen later to serve as the type (lectotype). The type automatically fixes the application of the name concerned.

It is clear from what is known of A. P. de Candolle's methods, and from his publications and those of others, that many of Mociño's illustrations served as types of names that he and his associates published. Since they did not see actual specimens of the plants from which the paintings were made, the paintings themselves represent the "one ... element used by the author." In the last century it has come to be accepted practice to treat the paintings in the de Candolle collection, and especially those listed in the Calques des Dessins, as "types," without much consideration of the fact that some (perhaps many) of them might not be holotypes, and that some might even be non-types. Now the previously uncontemplated appearance of the Torner Collection brings this into sharp focus. Plant nomenclature is full of necessary technicalities and unavoidable complexity, and in this instance hundreds of names of tropical American plants are involved. It thus becomes important to establish precisely, for each name based on a Mociño illustration, the type that determines for all time how that name is applied and may be used.

It is necessary to reconsider briefly the circumstances under which A. P. de Candolle first studied the paintings. He wrote that when he first saw them in Montpellier, he was struck by the beauty of some of them, by the considerable number of species that seemed to him to be new, and also by the numerous errors in the botanical names that had been given them. He made Mociño understand that it would be necessary to re-do the identifications, and he undertook to begin the task with him. In a much-quoted phrase, he said that when he saw that "the good old man had only the vaguest ideas of science," he determined to continue the work alone, to "resolve this chaos." He said clearly, "I had only the pictures [desseins], for the text itself was lost on the flight from Spain." He continued, "Thus I pursued my undertaking, and I succeeded in describing and classifying [with help from Dunal, according to a note by A. de Candolle], from the pictures alone, the thirteen or fourteen hundred species of this collection, and that with enough care, that when I met with the same species later, in the herbarium or in books, there were few changes to make in my work." It was also at this time, as mentioned above, that Node-Véran made the sketches of which many were eventually published in various Mémoires.

The implication is clear that de Candolle formed most of his ideas of what constituted new species and genera in the collection while he was studying it in Montpellier between 1812 and 1816. Presumably it was then that he added to the paintings the botanical names that are still to be found in the Torner Collection, written in his very characteristic hand. Judging from his own statement that his first descriptions needed hardly any revision in later years, it may reasonably be inferred that when the first volumes of the Prodromus began to appear, from 1824 to 1828, the descriptions citing the Sessé and Mociño illustrations were those he had written more than a decade before, with little or no modification.

The original paintings in the Torner Collection are certainly types of the related names published by de Candolle and his associates, unless special circumstances obtain. Probably few can be considered holotypes, because for most names published in 1817 and thereafter, it would theoretically be possible for de Candolle to have obtained some information from two or more sources (either from two or more original paintings, or partly from an original and partly later from a Geneva copy in his possession). When two or more paintings are involved, it seems technically necessary to choose a lectotype, case by case, as botanical specialists study the plants in question and make the necessary evaluations. The choice may be difficult when two originals, one in Pittsburgh and one in Geneva, are almost identical. On the other hand, it may be supposed that an original in Pittsburgh will usually be taken for lectotype over a copy in Geneva. Comparison of the two usually shows that the original is demonstrably better; as de Candolle himself said (1862, 290), the copies are not worth as much as the originals. As we have seen, his ideas were formed almost wholly from the originals.

In a very few special cases the paintings in the Torner Collection may plausibly be treated as holotypes, as previously suggested (McVaugh 1982). Some plates that were published to illustrate new species based on Mociño's paintings are not now represented in the de Candolle collection, though they were assigned numbers when A. P. de Candolle arranged them all in one systematic series in 1817. At least 26 of these, including members of the Annonaceae, Cactaceae, Caryophyllaceae, Crassulaceae, Dilleniaceae, Onagraceae, and Theaceae, were missing when A. de Candolle took inventory in 1873. All these except one cactus (Cereus oxypetalus DC.) are represented in the Torner Collection by original paintings annotated by de Candolle (or, for the three species of Annonaceae, by Dunal) with the names eventually published, or with near approximations of them, for example "Uvaria ? purpurea" for Unona violacea (1791), "Cactus cornigerus" for Echinocactus cornigerus (1714). On comparison, it is evident that the published plates are faithful copies of the paintings in the Torner Collection. Other paintings were apparently copied by Node-Veran in the early days but never were counted and numbered among the de Candolle collection. Some of these were published, including five species of Cassia, four of which were new (375, 489, 935, 1604, and 1766 in the Torner Collection, all annotated by de Candolle with the published names). Some others, including perhaps as many as 12 species of Solanum described by Dunal, were never published but are also represented in the Torner Collection by paintings, at least five with Dunal's annotations (58, 121, 461, 589, and 674).

It can hardly be a coincidence that so many paintings missing from de Candolle's collection correspond to those he knew had been published, or knew had been copied in anticipation of publication (as in the case of the cacti, which were not published until 1829, though one may assume that the copies had been made by Node-Véran before 1816). My supposition is that after the sketches were made for publication, the originals were returned to Mociño, and that when the entire series was taken to Geneva, de Candolle had no further use for the originals, as he already had available to him the sketches, a few published and others to be published. He therefore had no additional copies made in Geneva. I cannot explain why he numbered some of them (for example, all the Cactaceae), but not others (Cassia, Solanum).

In summation, there is a good case for treating as holotype an annotated painting in the Torner Collection if a new species has been based entirely upon it, if no copy of the painting exists in the de Candolle collection, and especially if there is evidence that this last is related to the fact that a contemporary copy of the original was published or was made for publication during the early days of de Candolle's interest in the paintings.

No discussion of the collection would be complete without a final word about the set of paintings that came back into Mociño's hands in Montpellier in May 1817. Little is known about when and how Mociño reached Barcelona. He wrote to de Candolle on 17 April 1817, from a place that he called "Alais" (now Alès, a town about 60 km north of Montpellier), at which time he was still waiting for the paintings. He wrote again from the same place, on 27 May and 17 July. Six months later (7 January 1818) Dunal wrote to de Candolle that Mociño had "passed through" Montpellier on his way to Spain. Rickett (1947) has recorded that he died, and was buried on 19 May 1820, in the Parochial Church of St. James, in what is now the heart of the old city of Barcelona. His epitaph was provided by his friend the Spanish botanist Mariano Lagasca, who wrote to de Candolle in November of the same year, "Mociño noster sex abhinc mensibus e vita discessit in urbe Barcinonensi ... Vir certe melioris fortunae dignus."

Fernando Altamirano (Altamirano, 1897), who went to Barcelona in 1898 to look for the missing paintings, said that he met a Sr. Felipe Esteva, who as a child had seen the paintings when his father had them; his grandfather had been the doctor who had kept them after caring for Mociño at the time of the latter's death. The paintings had ultimately passed to Sr. Esteva's uncle, Lic. D. Manuel Planos y Casals, who was thought to have given them to some public institution. Altamirano never succeeded in finding them. It must have been at this time, or perhaps before this, that the entire collection was acquired by a Catalonian bibliophile and historian, Lorenzo Torner Casas. His library eventually passed to his younger brother, and finally to his two nephews, Jaime and Luis Torner Pannocchia. In 1979 the brothers began negotiations with the Hunt Institute, to provide a place where the collection would be well curated and made fully accessible to the scientific and scholarly community. It eventually came to Pittsburgh in 1981.

The Torner Collection as Documentation for Sessé and Mociño's Published Works

As noted above, the posthumously published works of Sessé and Mociño, the Plantae Novae Hispaniae and the Flora Mexicana, include together more than a thousand validly published names of new species of plants. It is in the interest of the botanical world that these names be precisely identified, so that they may be applied properly, and used currently, in the somewhat remote chance that the species to which they apply were not given other names during the century that elapsed before their publication. Unfortunately it is not as easy to recognize types for these names as it is for those published by de Candolle. The species published in the volumes by Sessé and Mociño are well described, and at length, but as shown by surviving herbarium specimens, the authors often confused two or more species under the same name; in such instances a lectotype, or better a neotype, may be chosen from among their specimens, if it proves to be possible to reconcile any of the specimens with the original description. Sometimes the paintings prove to be very helpful in choosing a lectotype, providing as they do certain details of form and color that may not be clear from the Latin descriptions. When no acceptable specimen is known to exist, a painting may serve as a lectotype.

When the paintings were serially numbered, and the numbers cited in Flora Mexicana and Plantae Novae Hispaniae, as in the case of the Icones Florae Mexicanae, identification is relatively easy, especially when the paintings bear not only the serial numbers (these usually written in pencil by Mociño) but also contemporary names that were eventually published. About 189 of the 460 Icones were thought to represent new species, these published in one or both of the floras. As noted above, at least 150 of these can be satisfactorily identified in the Torner Collection, though often the names and serial numbers were omitted, and some numbers were partly or wholly trimmed off, when the collection was bound into volumes by a former owner. Substantial aid in the identification of individual paintings may be obtained by comparison with the duplicates and copies in Geneva, especially those representing the Icones Florae Mexicanae, which commonly bear the appropriate names or numbers, or both. A recent paper (McVaugh 1980) provides a synopsis of what is known about the Icones, including enumeration of those represented by original drawings and copies in the de Candolle collection, the names applied by Sessé and Mociño, and modern identifications made to the extent possible before the Torner Collection was known to the public.

It is clear that some of the Icones are missing from the collection in Pittsburgh; perhaps they were discarded at an early time, or lost in Geneva during the rush to copy them, or separated from the collection while it was out of sight in Barcelona. There appear to be no paintings of Begonia, for example, although four species, represented by Icones 285, 427, 428, and 429, were described as new by Sessé and Mociño. One of the cacti described by de Candolle in 1828, Cereus oxypetalus, was illustrated by an engraving made from one of Mociño's paintings, apparently Icon 94; no painting corresponding to this has been found in the Torner Collection. A few illustrations that are represented in Geneva by originals (duplicates) or copies, which have been photographed, are also apparently missing from the Torner Collection; at least, preliminary searches with the aid of the photographs have not established their presence. These include de Candolle numbers 71 (Sida carnea DC.), 100 (Montezuma speciosissima DC.), 174 (Colletia ? multiflora DC.), 381 (Cardionema multicaule DC.), 813 (Spigelia hedyotidea A.DC.), and 875 (Cordia crispiflora DC.). Some of these are not as easily recognized as Cereus and Begonia, and may eventually come to light.

Compared with the relatively rewarding process of matching names of species published by Sessé and Mociño with the numbered Icones, the identification of other names published by them is far more difficult. Most of the paintings made after 1791 were neither numbered nor provided with botanical names, so only by more subtle evidence can these sometimes be associated with published names and descriptions. Among Mociño's paintings, however, specialists will undoubtedly find answers to many problems, and this introduction may well end with the prospect that the Torner Collection will serve as a rich mine of information for years to come.

Selected References

Altamirano, F. "1897" [Dec. 1898 or early 1899]. Informe que tiene la honra de rendir al Señor Secretario de Fomento el Director del Instituto Médico Nacional. Anales Inst. Méd.-Nac. México 3: 286–293.

Alvarez Lopez, E. 1952. Noticias y papeles de la expedición científica Mejicana, dirigida por Sessé. Anales Jard. Bot. Madrid 10(2): 5–79 [reprint: 1–75].

Alvarez Lopez, E. 1953. Las tres primeras campanas de la expedición científica dirigida por Sessé, y sus resultados botánicos. Anales Inst. Bot. Cavanilles 11(1): 39–141 [reprint: 1–103].

Anonymous. 1971. The byways of research. Research news (University of Michigan) 21(10/11): 13–16.

Anonymous. 1981. Hunt Institute gets 200-year-old biodrawings. BioScience 31(7): 492.

Anonymous. 1982. The Hunt Institute has acquired long-lost art treasures. Guild of Natural Science Illustrators Newsletter 1982(10): 7–9.

Anonymous. 1982. Paintings from an expedition. Science News 121(12): cover, 202–203.

Arias Divito, J. C. 1968. Las Expediciones Científicas Españoles durante el Siglo XVIII: Expedicion Botanica de Nueva España. Madrid.

Arita, H. T. 1993. Diversidad de mamíferos terrestres. Ciencias, no. especial 7: 12–22.

Beltrán, E. 1952. Medio Siglo de Ciencia Mexicana, 1900–1950. Mexico.

Beltrán, E. 1968. Las reales expediciones botanicas del siglo XVIII a Hispanoamérica. Ciencia 26(3): 89–106; 26(4): 131–146.

Bernar, G. 1986. To the Totem Shore: The Spanish Presence on the Northwest Coast. [Spain.]

Blake, S. F. 1916. A revision of the genus Polygala in Mexico, Central America, and the West Indies. Contr. Gray Herb. 47: 1–122, pl. 1.

Blunt, W. 1950. The Art of Botanical Illustration. London. Pp. 169–172.

Candolle, A. de. 1874. Calques de Dessins de la Flore du Mexique, de Mocino et Sessé qui ont Servi de Types d'Espèces dans le Systema ou le Prodromus. 2 vols. Geneve. Pls. 1–250; 251–1171, I–XXXVIII, pp. 1–6.

Candolle. A. P. de. 1817–1821. Regni Vegetabilis Systema Naturale. 2 vols. Paris.

Candolle, A. P. de. 1824–1873. Prodromus Systematis Naturalis Regni Vegetabilis. 17 vols. Paris.

Candolle, A. P. de. 1862. Mémoires et Souvenirs de Augustin-Pyramus de Candolle, ed. A. de Candolle. Paris and Geneva.

Carreño, A. M., ed. 1913. Noticias de Nutka. I–CIX, Portado del Manuscript. Sociedad Mexicana de Geografia y Estadistica, México. [Includes a long introduction by Carreño (pp. I–CIX); the "Noticias" proper, comprising 12 "articulos" by Mociño (pp. 1–79); an "Apendice del Diccionario de Nutka," by Mociño (pp. 81–100); and a description of the Volcano of Tuxtla, Veracruz, written by Mociño in 1793.]

Coats, A. M. 1969. The Plant Hunters. New York. Pp. 335–337.

Engstrand, I. H. W. 1962. Scientific Aspects of Spanish Exploration in New Spain during the Late Eighteenth Century. Doctoral thesis. Los Angeles, University of Southern California.

Engstrand, I. H. W. 1981. Spanish Scientists in the New World: The Eighteenth-Century Expeditions. Seattle and London.

Engstrand, I. H. W. 1983. A begonia discovery: Paintings hidden in Spain since 1700s. The Begonian 50: cover, 4–9.

Engstrand, I. H. W. 1983. Pictures from an expedition. The Sciences 23(5): 52–57.

Engstrand, I. H. W. 1984. The unopened gift: Spain's contributions to science during the Age of Enlightenment. Terra 22(6): 12–17.

Engstrand, I. H. W. 1990. Mexico's pioneer naturalist and the Spanish enlightenment. The Historian 53(1): 17–32.

Fernández Casas, J., M. A. Puig-Samper and F. J. Sánchez García, eds. 1993. Guatimalensis prima flora. Fontqueria 37: [1–3], 4–140.

Fleming, T. 1983. They've found the missing masterpieces. International Wildlife 13(1): 19–24.

Germán Ramírez, M. T. 1994. Iconografía inédita de la Flora Mexicana, obra de Sessé y Mociño, en el Acervo Histórico del Herbario Nacional de México, MEXU. Bol. Soc. Bot. México 54: 69–97.

Giménez, M. A., J. M. Losa and J. L. Valverde. 1993. José Mariano Mociño's "Flora de Guatemala" in the Real Jardín Botánico de Madrid, transl. R. Losa. Huntia 9(1): 21–30.

Greuter, W. et al. 1994. International Code of Botanical Nomenclature Adopted by the Fifteenth International Botanical Congress, Yokahama, August–September 1993. Königsten.

Grobet Palacio, R. 1982. El Peregrinar de las Flores Mexicanas: Jose Mariano Mocino y Losada 1757–1822. Xalapa, Veracruz.

[Kiger, R. W.] 1981. Long-lost Sessé and Mociño illustrations acquired. Bull. Hunt Inst. Bot. Doc. 3(1): 1–2.

Lamas, G. 1986. Ilustraciones inéditas de lepidópteros mexicanos de la expedición de Sessé y Moziño (1787–1803). Revista de la Sociedad Mexicana de Lepidopterologia 10(2): 27–34.

Large, A. J. 1984. North and South of Lewis and Clark. We Proceeded On: Official Publication of Lewis & Clark Trail Heritage Foundation, Inc. 10(4): 8–12.

Leuenberger, V. B. E. 1988. Zur Geschichte der Taxonomie von Pereskia lychnidiflora DC., P. zinniiflora DC. (Cactaceae) und ihrer Synonyme. Beitr. Biol. Pflanzen 63: 179–198.

Longinos Martínez, J. 1961. Journal of José Longinos Martínez: Notes and Observations of the Naturalist of the Botanical Expedition in Old and New California and the South Coast, transl. and ed. L. B. Simpson. San Francisco.

Maldonado Polo, J. L. 1996. Flora de Guatemala de José Mociño. Madrid.

McCoy, C. J. and O. A. Flores-Villela. 1985. Amphibians and reptiles of the Sessé & Mociño Expedition: A lost chapter in Mexican herpetology. Ann. Carnegie Mus. 54(5): 189–193.

McCoy, C. J. and O. A. Flores-Villela. 1986. The identity of Coluber nutkensis (Reptilia: Serpentes). Canadian Field-Naturalist 102: 716–718.

McVaugh, R. 1945. The jatrophas of Cervantes and of the Sessé & Mociño herbarium. Bull. Torrey Bot. Club 72: 32–41.

McVaugh, R. 1969. El itinerario y las colectas de Sessé y Mociño en México. Bol. Soc. Bot. México 30: 137–142 [map p. 142].

McVaugh, R. 1972. Botanical exploration in Nueva Galicia, Mexico, from 1790 to the present time. Contr. Univ. Michigan Herb. 9: 205–357 [Sessé & Mociño, pp. 305–310].

McVaugh, R. 1977–1990. Botanical results of the Sessé & Mociño Expedition (1787–1803). I. Summary of excursions and travels. II. The Icones Florae Mexicanae. III. The impact of this and other expeditions on contemporary botany in Europe. IV. The library and the herbarium of the expedition. Contr. Univ. Michigan Herb. 11: 97–195; 14: 99–140; 16: 155–171; 17: 183–214.

McVaugh, R. 1982. The lost paintings of the Sessé & Mociño expedition: A newly available resource. Taxon 31(4): 691–692.

McVaugh, R. 1995. Resultados botánicos de la expedición de Sessé y Mociño (1787–1803). [V, although not so designated in the text]. El impacto sobre la botánica moderna in América tropical. In: S. Guevara et al., eds. 1995 [Copyright 1992, "Primera edición: 1993", printed Dec. 1994, distrib. May 1995]. Logros y Perspectivas del Conocimiento de los Recursos Vegetales de México en Vísperas del Siglo XXI. Inst. de Ecología, S.A., Xalapa, Veracruz. Pp. 1–5.

McVaugh, R. 1998. Botanical results of the Sessé & Mociño expedition (1787–1803). VI. Reports and records from western Mexico, 1790–92. Bol. Inst. Bot. Univ. Guadalajara 6(1): [1]–178.

McVaugh, R. 2000. Botanical Results of the Sessé & Mociño Expedition (1787–1803) VII. A Guide to Relevant Scientific Names of Plants. Pittsburgh.

Moçiño, J. M. 1970. Noticias de Nutka: An Account of Nootka Sound in 1792, transl. and ed. I. H. Wilson [later Engstrand]. Seattle and London. [American Ethnological Society Monograph 50.]

Nelson Sutherland, C. 1997. Material tipo de la colección de Sessé y Moçiño en el Real Jardín Botánico de Madrid. Anales Jard. Bot. Madrid 55(2): 375–418.

Perret, P. La Flore des Dames de Genève. 1988. Musées de Genève 284: 17–21.

Ramírez, R. 1891. Reseña de la expedición de historia natural. Naturaleza (Mexico City), ser. 2. 2, app.: i–xi.

Rickett, H. W. 1947. The Royal Botanical Expedition to New Spain. Chron. Bot. 11(1): 11–86.

Rollins, R. C. 1960. The American Cruciferae of Sessé and Mocino [sic]. Rhodora 62(733): 11–20.

Sessé y Lacasta, M. de and J. M. Mociño. 1887–1891. Plantae Novae Hispaniae. Naturaleza (Mexico City), ser. 2. 1, app.

Sessé y Lacasta, M. de and J. M. Mociño. 1891–1897. Flora Mexicana. Naturaleza (Mexico City), ser. 2. 2, app.

Sessé y Lacasta, M. de and J. M. Mociño. 1893. Plantae Novae Hispaniae, ed. 2. Mexico City.

Sessé y Lacasta, M. de and J. M. Mociño. 1894. Flora Mexicana, ed. 2. Mexico City.

Sprague, T. A. 1926. Sessé and Mociño's Plantae Novae Hispaniae and Flora Mexicana. Bull. Misc. Inform. Kew 1926: 417–425.

Standley, P. C. 1920. Trees and Shrubs of Mexico. Contr. U.S. Natl. Herb. 23(1): 13–18.

Voss, E. G. et al. 1983. International Code of Botanical Nomenclature Adopted by the Thirteenth International Botanical Congress, Sydney, August 1981. Utrecht.

White, J. J., R. McVaugh and R. W. Kiger. 1998. The Torner Collection of Sessé & Mociño Biological Illustrations CD-ROM. Pittsburgh.