3. Cleistes Richard ex Lindley, Gen. Sp. Orchid. Pl. 409. 1840.
Spreading pogonia [Greek kleistos, closed, alluding to lip and petals that diverge only near apex, forming tube for most of their length, the flower thus appearing closed]
Katharine B. Gregg & Paul M. Catling
Herbs, terrestrial. Roots 1–2 mm wide, sometimes with wider nodular tuberoids, frequently rather brittle. Leaves 1–3 on vegetative plants, 1(–2) centrally on flowering stems, sessile; blade oblong-lanceolate or elliptic-oblong. Inflorescences terminal,1–3-flowered; floral bracts leaflike. Flowers resupinate, erect, sessile; sepals olive-green, brown, or maroon, linear-lanceolate, apex acuminate; petals rose-pink to white, spatulate or oblanceolate, usually forming tube with lip; lip rose-pink to white, with rose or purple veins, oblanceolate, 3-lobed, middle lobe medially winged or tuberculate, central keel grooved from base to 3/4 its length; column free, white, apex lacerate, truncate; anther terminal, hinged; pollinia 2, without viscidium, soft, mealy; pollen grains in tetrads. Fruits capsules, erect, cylindric.
Species ca. 25 (2 in the flora): tropical and subtropical regions, mostly South America, 2 in Central America.
Authors of some neotropical floras have questioned the separation of Cleistes from Pogonia; most recent North American authors have followed O. Ames (1905–1922) in recognizing Cleistes, and we prefer to do the same until a detailed study suggests otherwise. The two North American species can reproduce asexually by root shoots.
SELECTED REFERENCES
Ames, O. 1905–1922. Orchidaceae: Illustrations and Studies of the Family Orchidaceae Issuing from the Ames Botanical Laboratory…. 7 vols. Boston and New York. Vol. 7. Catling, P. M. and K. B. Gregg. 1992. Systematics of the genus Cleistes in North America. Lindleyana 7: 57–73. Fernald, M. L. 1946b. Some orchids of the Manual range. Rhodora 48: 161–162, 184–197, plates 1045–1048.
