Orchids

Coelogyneae, mostly epiphytes, and inhabitants of tropical Asia. A single internode of each shoot is swollen to form a pseudobulb.

Liparideae, terrestrial, two, Malaxis and Corallorhiza, are British and North American. Liparis is a large genus widely distributed in the tropics.

Pleurothallidieae, natives of tropical America, one of which, Pleurothallis, contains about 500 species. Masdevallia is common in cultivation and has often brilliant scarlet, crimson or orange flowers.

Laelieae,

natives of the warmer parts of America, including three of those best known in cultivation, Epidendrum, Cattleya and Laelia.

Phajeae, chiefly tropical Asiatic, some—Phajus and Calanthe spreading northwards into China and Japan.

Cyrtopodieae, tropical, but extending into north temperate Asia and South Africa; Eulophia and Lissochilus are important African genera.

Cataseteae,

with tropical American genera, two of which, Cata selum and Cycnoches, have di- or tri-morphic flowers.

Dendrobieae,

in the warmer parts of the Old World; the chief genus is Dendrobium, with 75o species, often with showy flowers.

Cymbidieae, in the tropics of the Old World. The leaves are generally long and narrow. Cymbidium is well known in cultiva tion.

Oncidieae,

in the warmer parts of America. Odontoglossum and Oncidium include some of the best-known cultivated orchids.

Sarcantheae,

in the tropics. V anda (Asia) and Angraecum (Africa and Madagascar) are known in cultivation. The flower of Angraecum sesquipedale has a spur 18 in. in length.

British Orchids.—The family is well represented in Great Britain by nearly 4o species representative of i8 genera; among these are several species of Orchis, Gymnadenia (fragrant orchis), Habenaria (butterfly and frog orchis), Aceras (man orchis), Her minium (musk orchis), Ophrys (bee, spider and fly orchis), Epi pactis (helleborine), Cephalanthera, Neottia (bird's-nest orchis), one of the few saprophytic genera, which have no green leaves, but derive their nourishment from decaying organic matter in the soil, Listera (tway blade), Spiranthes (lady's tresses), Malaxis (bog-orchis), Liparis (fen-orchis), Corallorhiza (coral root), also a saprophyte, and Cypripedium (lady's slipper), represented by a single species now very rare in limestone districts in the north of England.

North American Orchids.

In North America north of Mex ico about 140 species of orchids are found, representing some 4o genera (see 0. Ames, An Enumeration of the Orchids of the United States and Canada, 1925). Many are widely distributed across the continent, some extending to Alaska and even to Green land, but they occur most numerously in the eastern and especially the south-eastern States. The generic groups having the largest number of species are the rein-orchises (Habenaria), 32 species; lady's-tresses (Spiranthes), is species; lady's-slippers (Cypri pedium), 10 species; and bog-orchises (Malaxis), 8 species. The tropical epiphytes are represented by Epidendrum, 9 species, and Oncidium, 4 species, found in Florida. Among the many attractive

orchids native to the eastern States and Provinces are the showy lady's-slipper (C. regime), the yellow lady's-slipper (C. parvi forum), the moccasin-flower (C. acaule), the showy orchis (Orchis spectabilis), the round-leaved rein-orchis (Habenaria rotundi folio), the white-fringed rein-orchis (H. blephariglottis), the yel low-fringed rein-orchis (H. ciliaris), the purple-fringed rein-orchis (H. psychodes), the rose-pogonia or snake-mouth (Pogonia ophioglossoides), the dragon's-mouth (Arethusa bulbosa) and the grass-pink (Limnodorurn tuberosum).

In the Rocky Mountain region and adjacent plains some 4o species of orchids occur; fully half of these are found also in the eastern States and a dozen or more extend northward to Alaska. Among them are the mountain lady's-slipper (Cypripedium mon tannin), the oval-leaved rein-orchis (Habenaria Menziesii), and the round-leaved orchis (Orchis rotundifolia), which ranges north ward to the Yukon and to Greenland. About 35 species of orchids occur in the Pacific States; among these are the California lady's slipper (Cypripedium californicum), the Sierra rein-orchis (Hab enaria leucostachys), the giant helleborine (Epipactis gigantea) and the rare phantom orchis (Cephalanthera Austinae).

Cultivation.

The only orchid of substantial economic im portance, furnishing a staple article of extensive use is vanilla (q.v.). But the number of tropical orchids grown in greenhouses in Europe and North America for the flower markets, and as ob jects of horticultural and scientific interest is immense. More than 3,00o species, many of them epiphytes, are in cultivation, as well as many thousand hybrid forms derived from them. Among the genera thus represented in orchid culture are Cattleya, Cor dula, Dendrobium, Epidendrum, Laelium, Odontoglossum, and Phalaenopsis. Propagation of these cultivated forms is by divi sion, cuttings and growth from seed. Many terrestrial orchids practically defy all efforts at cultivation, due to lack of knowl edge regarding soil conditions, to saprophytic habits, and to their growth in association with special fungi (see MYCORRHIZA).

BIBLIOGRAPHY.-Descriptive: A. Engler and K. Prantl, Die Natur lichen Pfianzenfamilien (1887-1909) ; F. Kraenzlein, Orchidacearum Genera et Species (Berlin, 1897-1901) ; A. D. Webster, British Orchids (2 ed., 1898) ; W. H. Gibson and H. L. Jeliffe, Our Native Orchids (1905) ; 0. Ames, Orchidaceae (1905-22) and An Enumeration of the Orchids of the United States and Canada (Boston, 1924). Cultiva tion: J. Veitch, Manual of Orchidaceous Plants Cultivated under Glass in Great Britain (1887-94) ; F. Boyle, About Orchids (1893) ; C. H. Curtis, Orchids for Everyone (1910) ; C. Harrison, Commercial Orchid Growing (1914) ; C.F., F.K. and L.L. Sander, Sander's Orchid Hybrids (1921) and Sander's Orchid Guide (1927) ; A. E. White, American Orchid Culture (1927) ; F. Norris and E. A. Eames, Our Wild Orchids: How to Find and Know Them (American: 1929).