Isotria

Rafinesque

Med. Repos., hexade 2, 5: 357. 1808.

Common names: Whorled pogonia orchid
Etymology: Greek iso, equal, and tri, 3 probably referring to 3 sepals of equal size and shape
Treatment appears in FNA Volume 26. Treatment on page 511. Mentioned on page 496.
Revision as of 22:12, 27 May 2020 by imported>Volume Importer

Herbs, perennial, terrestrial, winter dormant. Roots long, slender, hairy with mycorrhizae. Stems simple, hollow, fleshy, smooth, glaucous. Leaves (2–)5(–6), appearing whorled. Inflorescences terminal; bracts absent. Flowers 1–2, resupinate, erect, yellowish green to white, yellow, and purple, subsessile to pedicellate; sepals of same color, linear-oblanceolate to lanceolate, of equal size; petals oblanceolate, elliptic-obovate, or elliptic-lanceolate, enclosing column; lip apically 3-lobed, lateral lobes triangular, margins involute; callus forming fleshy medial crest; column white, apex denticulate; anther operculate; pollinia 2, hinged, soft, mealy; rostellum obscure; pollen in tetrads, granular; ovary green, slender. Fruits capsules, commonly persistent through following growing season, erect, ellipsoid-cylindric, dehiscent in fall. Seeds 1.2 × 0.2 mm. x = 9.

Distribution

e North America.

Discussion

Species 2 (2 in the flora).

Key

1 Sepals green to light green, less than 30 mm; lip light yellowish green to pale greenish white, streaked with green; pedicel of mature capsule 5–17(–20) mm; stem and leaves pale grayish green. Isotria medeoloides
1 Sepals purplish brown, greater than 30 mm; lip yellowish green to white, streaked with purple; pedicel of mature capsule 20–55 mm; stem purplish to brownish green; leaves green to dark green. Isotria verticillata
... more about "Isotria"
Loyal A. Mehrhoff +  and Michael A. Homoya +
Rafinesque +
Whorled pogonia orchid +
e North America. +
Greek iso, equal, and tri, 3 +  and probably referring to 3 sepals of equal size and shape +
Med. Repos., hexade +
ames1905a +, homoya1977a +  and mehrhoff1983b +
Isotria +
Orchidaceae (tribe Vanilleae) subtribe Pogoniinae +