Herbs, perennial, terrestrial, apparently epiphytic in one species, photosynthetic to mycotrophic. Roots fleshy, with a few filiform roots from stem base, some terminating in tuberoids. Stems erect, usually simple, terete, succulent, glabrous. Leaves 1–10, alternate and distichous, or solitary at midstem, without stipules, glabrous, sessile, not articulate, clasping stem; blade lance-ovate to ovate, or reduced to sheathing bracts. Inflorescences terminal, solitary or 1–10-flowered racemes, flowers axillary or terminal, arrangement spiral; floral bracts consisting of smaller proximalmost leaves, ovate to cordate, foliose. Flowers resupinate or not, short-pedicellate; sepals and petals distinct and free; dorsal sepal lanceolate to oblanceolate; lateral sepals lanceolate, slightly falcate; petals linear-lanceolate to lanceolate; lip clawed, 3-lobed; disc with 3 lines or crests; column slender, 5–10 mm, footless; anther erect, white or pale green (with magenta margins in Triphora trianthophora), short-stalked, not articulate, rigid; pollinia 2; pollen in tetrads, soft, mealy; ovary fusiform, slender; stigma proximal to anther, entire or 2-lobed; rostellum simple or absent. Fruits capsules, erect or pendent, ellipsoid-ovoid or obovoid, with 6 low, narrow keels.

Distribution

e North America, West Indies, Central America, South America.

Discussion

Species ca. 25 (5 in the flora).

Most species of Triphora exist in small, scattered populations and exhibit synchronous, ephemeral flowering; flowers last only one day. Synchrony enhances the chances for fertilization. Isolated flowers are rarely fertilized.

Selected References

Ames, 0. 1905–1922. Orchidaceae: Illustrations and Studies of the Family Orchidaceae Issuing from the Ames Botanical Laboratory…. 7 vols. Boston and New York. Vol. 7.

Medley, M. E. 1996. Notes on collections of Triphora (Orchidaceae) from the American tropics. Selbyana 17: 83–87.

Lower Taxa

Triphora amazonica, Triphora craigheadii, Triphora gentianoides, Triphora trianthophoros, Triphora yucatanensis

Key

1	Flowers not resupinate, lip facing stem at anthesis, always erect; column yellowish.	> 2
1	Flowers resupinate, lip facing away from stem at anthesis, erect or nodding; column white or pale green.	> 3
2	Leaves bractlike, ascending, usually partially sheathing stem; inflorescences corymbose racemes.	Triphora gentianoides
2	Leaves not bractlike, diverging at ± right angles from stem; inflorescences racemes, not corymbose.	Triphora yucatanensis
3	Leaves deep purple abaxially, often faded on dried specimens, ovate to cordate, not reniform; flowers 1–3; lip white with irregular purple spots, disc with 3 parallel white longitudinal crests, not papillose; pollinia yellow.	Triphora craigheadii
3	Leaves green to yellow-green on both surfaces, sometimes veined with purple abaxially, broadly ovate to nearly reniform; flowers 1–6; lip white, disc with 3 green longitudinal crests, papillose; pollinia yellow or magenta.	> 4
4	Flowers (1–)3–6(–20), lip crests bright green; leaves ovate; pollinia magenta.subsp. trianthophoros	Triphora trianthophoros
4	Flowers 1, lip crests pale green; leaves broadly ovate to reniform; pollinia yellow.	Triphora amazonica