Gyrostachys gracilis (Bigel.) O. Ktze., Ibidium grocile (Bigel.) House. 



In sandy post oak woods, gravelly soils, on open-wooded slopes, in mucky or 

 boggy soil in low pineiands, in savannahs and coastal prairies, swamps and ever- 

 green shrub bogs, in fields, meadows and prairies of n.-cen., e. and s.e. Tex., 

 July-Oct.; from N.S. and N.B.. s. to s.-cen. Fla., w. to Minn., la.. Mo., Okla. 

 and Tex. 



The broad green stripe in the center of the lip, which is rarely more than 

 5 mm. long, is distinctive. Also, the usually fugacious basal leaves are ovate to 

 ovate-lanceolate instead of being grasslike as in most of our species. 



Var. brevilabris (Lindl.) Correll. Texas ladies" tresses. Similar to var. gracilis 

 except for the densely pubescent spike, persistent basal leaves, and earlier flower- 

 ing period in March and May. Spiranthes brevilabris Lindl. Originally described 

 from Tex., this variety is rare from s. Tex., e. to Fla. in habitats similar to those 

 of var. gracilis. 



Var. floridana (Wherry) Correll. Florida ladies' tresses. Similar to var. gracilis 

 except for the lip having a yellow instead of green center and the much narrower 

 and elongated basal leaves being persistent; also flowering earlier, from April to 

 June. Ibidium floridanum Wherry. Occurring in habitats similar to var. gracilis 

 from N.C., s. to cen. Fla. and w. to Tex. 



4. Spiranthes longilabris Lindl. Giant spiral-orchid. Fig. 374. 



Plant erect, slender, flexuous, essentially glabrous throughout, occasionally 

 pubescent above, 1.2-6 dm. tall; roots fleshy, numerous, fasciculate; leaves (when 

 present) basal, linear to narrowly lanceolate, acute, 3-10 cm. long, mostly less 

 than 5 mm. wide, reduced above to sheathing bracts; spike slender, secund, only 

 slightly spiraled at most, 5-14 cm. long; floral bracts broadly ovate to ovate- 

 lanceolate, acuminate-elongate, 5-12 mm. long; flowers white or white tinged with 

 cream-color, conspicuously ringent, tubular, projecting almost horizontally away 

 from the rachis; sepals 6-10 mm. long, 2-3 mm. wide; dorsal sepal oblong-elliptic 

 to oblong-lanceolate, subacute to acute; lateral sepals linear-lanceolate, spreading 

 and recurved upward; petals linear, obtuse to subacute, 6.5-9 mm. long, about 1 

 mm. wide; lip yellow-white, narrowly ovate to ovate-oblong, from a broadened 

 base, tapering to the obtuse to subacute apex, strongly arcuate-recurved, usually 

 somewhat dentate or crenatc along the apical margin, 6—10 mm. long, 3-5.5 mm. 

 wide near the base, callosities rather slender; column about 4 mm. long. 



Commonly in wet grassy pine barrens and flatwoods, swamps, marshes, wet 

 savannahs and prairies, and sandy bogs in s.e. Tex., Oct-Dec; from e. N.C., s. to 

 Fla.. and w. to Tex. 



The characteristically secund inflorescence of horizontally projecting flowers 

 separates this species from all other of our Spiranthes. Its nearest ally, S. praecox, 

 with which it may be confused, has flowers whose lips are marked or veined with 

 green, a character lacking in 5. longilabris. 



5. Spiranthes praecox (Walt.) Wats. Grass-leaved ladies' tresses. Fig. 374. 

 Plant usually slender, essentially glabrous throughout, occasionally sparsely 



pubescent above, 2-7.5 dm. tall; roots rather slender, elongated, fasciculate; leaves 

 (when present) as many as seven, mostly basal, narrowly linear to filiform, 10-25 

 cm. long, 1-5 mm. wide; spike loosely to densely flowered, spirally twisted or 

 often nearly secund, 3-15 cm. long, about 1.5 cm. in diameter; floral bracts 

 ovate-lanceolate, acuminate-attenuate, often with strongly hyaline margins, 4-15 

 mm. long; flowers white, or white and veined and marked with green; sepals 

 usually pubcrulcnt on the outer surface, 5.5-10 mm. long, 2-3 mm. wide; dorsal 

 sepal oblong-elliptic to lanceolate, subacute, often slightly constricted near the 

 apex; lateral .sepals lanceolate, acute; petals coherent with the dorsal sepal, linear, 



730 



