Bryophytes (mosses, hepatics and hornworts) are small, terrestrial, photosynthetic, spore-bearing plants in which the gametophyte (haploid) generation is dominant. Bryophytes are important pioneers on rock or disturbed sites and they help create soil conditions amenable to the establishment of larger plants. They also provide habitats in their colonies for smaller organisms such as algae, cyanobacteria and small animals. Bryophytes are most profuse in tropical rainforests and boreal forests, where they may form a significant proportion of the biomass. The moisture that is held in the large, often festooning mats of bryophytes contributes significantly to the ambient humidity in such habitats.
In 2000, the NYBG bryophyte herbarium was named the William C. Steere Bryophyte Herbarium, in honor of one of the 20th century’s most influential bryologists. William C. Steere served as President of The New York Botanical Garden from 1958-1972. The Steere Bryophyte Herbarium holds perhaps the most important collection of bryophytes in the world in terms of the number of specimens, and the geographical and taxonomic depth and breadth. The herbarium contains approximately 640,000 specimens (520,000 mosses and 120,000 hepatics and hornworts). Of this total, approximately 24,500 (4%) are type specimens. This is the largest bryophyte herbarium in the Western Hemisphere and is among the five largest worldwide. The collection continues to grow actively today through staff collections and exchange. The emphasis is on collections from the Western Hemisphere, but virtually all areas of the world are represented.
The nucleus is the Columbia University herbarium, which already contained two important bryophyte components when it came to NYBG in 1895. One was the herbarium of August Jaeger (1842-1877),
which contained about 12,500 specimens of mosses, the basis for a series of articles by Jaeger (and later F. W. Sauerbeck) that reviewed all known moss species. The Jaeger Herbarium contains
duplicates of type specimens described by a range of other 19th century bryologists; its holdings of specimens described by Carl Müller and Ernst Hampe are especially important, since the
primary herbarium of deposit of types of species described by Müller, the Botanischer Garten und Botanisches Museum Berlin-Dahlem Berlin (B), was destroyed during World War II. The second of
the herbaria incorporated at the founding of the institution was the moss herbarium of Coe F. Austin (1831-1880), one of North America’s first bryologists, who made extensive collections in
New Jersey and southern New York State.
The Garden’s single largest bryological acquisition was the purchase in 1906 of the herbarium of William Mitten (1819-1906), which consisted of approximately 50,000 specimens of mosses and hepatics from all continents of the world. Mitten served unofficially as bryologist for the Royal Botanic Gardens at Kew and had free access to the bryophyte collections from the many botanical expeditions sponsored by the British Government in the 19th century. Mitten’s 72 publications described over one thousand new species based on the collections made on some of the most famous 19th century scientific expeditions: J.D. Hooker’s collections made in southern South America, Australia, New Zealand and other south temperate areas on the Antarctic voyage of H.M. discovery ships Erebus and Terror (1839-1843) and his exploration of the Himalayan region with Thomas Thompson from 1847-1851; Richard Spruce’s collections from his 15 years of botanical collecting in South America (1849-1864); collections by I. B. Balfour, Mungo Park and Gustav Mann from Africa; and collections by Allan Cunningham and Ferdinand von Mueller from Australia and New Zealand, and David Douglas and Charles Lyall from North America. A relatively small number of collections by Charles Darwin on the voyage of the Beagle are also included.
In 1945 the Garden acquired the herbarium of Princeton University. Bryologically this was important because of the collections of Per Karl Hjalmar Dusén (1855-1926) from southern Argentina and Chile and the collections of J. B. Hatcher, identified by Dusén, from the Princeton University Expeditions to Patagonia in 1896-1899. In 1968 the Arctic bryophytes of Stanford University (4580 specimens) were transferred to NY when Steere, previously Dean of the Graduate School at Stanford, moved to NY to take over the directorship. Additional bryophyte herbaria acquired include University of Kansas (1969), Florida State University (1973) DePauw University (1986) and Wellesley College (1988). A more comprehensive list of the major collectors represented in the herbarium is also available.
Because of the firm foundation Britton laid to the bryophyte herbarium, bryology has had a traditionally prominent position in the research program at The New York Botanical Garden since its
inception. Elizabeth G. Britton was the wife of the founder and first Director of the New York Botanical Garden, Nathaniel L. Britton. Elizabeth Britton was a respected bryologist and very
influential in the American bryological community. She collected extensively in the West Indies and North America, and published many articles on bryophytes. Britton had a wide correspondence
and active exchange program and, thus, obtained much type and authentic material from colleagues around the country and from Europe. Other staff members active in bryology in the early years
of the institution were Lucien Underwood, whose personal herbarium included, in addition to his own types, a very nearly complete set of Richard Spruce’s species described in his Hepaticae
Amazonicae et Andinae, Marshall A. Howe, who was the first professionally trained bryologist to collect in California and whose research findings were recorded in his hepatic flora of
California, and R S. Williams, who collected extensively in Peru, and became the Garden’s first expert in non-North American bryophytes.
The tradition of bryological research at NYBG continues to the present. William R. Buck has published extensively on the systematics of pleurocarpous mosses and the moss floras of the Greater Antilles and central French Guiana. In addition to studies of the hepatic family Lejeuneaceae, Barbara Thiers has headed up projects to index type specimens of Mitten and Spruce and to database the bryophyte herbarium, resulting in the American Bryophyte Catalog.