The Ray Ethan Torrey Botanical Greenhouse currently housed by the Department of Biology includes nearly 700 genera in more than 225 families. The collection is especially rich in “basal angiosperms,” including members some of the most primitive families of flowering plants.
Of particular interest in this regard are plants of Amborella trichopoda of the family Amborellaceae, which is widely considered to represent the most primitive living angiosperm. This rare plant, a native of New Caledonia, is one of a handful of living flowering plants that are primitively vesselless, instead making wood that, like that of gymnosperms, has only tracheids and lacks vessel members.
Another rare, primitive angiosperm in the collection is Austrobaileya, of the family Austrobaileyaceae. This plant, a native of Queensland, Australia, has exceedingly primitive, leaf-like stamens that have no anther— rather the pollen sacs, technically microsporangia, attach directly to a laminar stamen instead of forming the typical terminal anther that is characteristic of most angiosperms.
Other primitive angiosperms in the collection include Annona muricata (the sour sop) of the family Annonaceae, Chloranthus and Hedyosmum of the family Chloranthaceae, Illicium (the star anise) of the family Illiciaceae, and Drimys and Pseudowintera of the family Winteraceae. The Winteraceae, like the Amborellaceae, is a family of primitively vesseless angiosperms.
The collection also contains a number of interesting economic plants, including Myristica (nutmeg) of the family Myristicaceae; Cinnamomum (cinnamon) and Laurus (true laurel or bay) of the family Lauraceae; Mangifera (mango) of the family Anacardiaceae; Durio (the durian) of the family Bombacaceae; Ananas (the pineapple) of the family Bromeliaceae; Hevea (rubber), Manihot (cassava, tapioca), and Ricinus (castor oil plant) of the family
Euphorbiaceae; Oryza (rice), Hordeum (barley), and Saccharum (sugar cane) of the grass family (the Gramineae); Gossypium (cotton) of the family Malvaceae; Swietenia (mahogany) of the family Meliaceae; Ficus (fig) of the family Moraceae; Musa (banana) of the family Musaceae; Olea (olive) of the family Oleaceae; Piper (black pepper) of the family Piperaceae; Punica (pomegranate) of the family Punicaceae; Coffea (coffee) of the family Rubiaceae; Nicotiana (tobacco) of the family Solanaceae; Theobroma (cocao) of the family Sterculiaceae; Camellia (tea) of the family Theaceae; and Zingiber (ginger) of the family Zingiberaceae.
Carnivorous plants are another group which is of particular interest. Our living collections contain a number of carnivorous angiosperms, including Drosera (sundew) and Dionaea (Venus-fly-trap) of the family Droseraceae; Pinguicula (butterwort) and Utricularia (bladderwort) of the family Lentibulariaceae; Nepenthes (Old World pitcher plant) of the family Nepenthaceae; and Sarracenia and Darlingtonia of the family Sarraceniaceae (the New World pitcher plant family).
Other flowering plants in the living collection that are particularly notable include Gunnera of the family Gunneraceae, which often contains symbiotic cyanobacteria in its tissues; Passiflora (the passion flower) of the family Passifloraceae, one of the few familes of angiosperms that has an androgynophore; and Akebia of the family Lardizabalaceae, which has the unusual character of having a dehiscent berry.
In addition to flowering plants the living collections also contain a number of notable gymnosperms. Included among these are Gnetum, Ephedra, and Welwitschia of the order Gnetales, which are characterized by the unusual character (for gymnosperms) of having vessels. The genus Welwitschia is an especially bizarre plant that comes from the Angolan and Namibian desert and has only two leaves throughout its entire life even though it may grow to be hundreds of years old. Welwitschia is dioecious and our collection contains large plants of both sexes, each of which have flowered recently.
The collection also holds a number of cycads, primitive gymnosperms that go back to the age of the dinosaurs, and which, like Ginkgo, retain motile, flagellate sperm cells. Cycads in the collection include Bowenia, Dioon, Cycas, Encepharlartos, Zamia, Microcycas, and Stangeria. The genus Microcycas, which is endemic to a very restricted area of Cuba, is one of the rarest of cycads. Stangeria when first discovered in South Africa was sent back to the Royal Botanic Gardens at Kew and first described as a fern. It was only later when it produced cones that it was realized that it was actually a gymnosperm.
Finally, the collection also contains a number of notable pteridophytes (seedless vascular plants), including Psilotum, which is so primitive that is consists only of stems, lacking both roots and leaves. Other interesting pteridophytes include tree ferns such as Angiopteris and Marattia of the family Marratiaceae, Cyathea of the family Cyatheaceae, and Dicksonia of the family Dicksoniaceae, horsetails (the genus Equisetum), the floating fern Salvinia, and Isoetes (the quillwort) of the family Isoetaceae, which is a living descendant of the giant tree lycopods of the Carboniferous coal swamps.