ORDER 137. ORCHIDACE^E. 325 



3. VALLISNERIA, Mich. EEL-GRASS. Fls. $ ? . Spathe ovate, 2- 

 4-parted. $ Spadix or spike covered with minute naked fls. ? Fl. soli- 

 tary, a slender perianth with linear scgm. and 3 bifid stig. Fr. cylindrical, 



00 -seeded. .!(.? Fertile flowers on long spiral scapes. July, Aug. 



V. spiralis L. Lvs. 1 2f long, obtuse, J-' wide, scapes of the sterile plants short, of 

 the fertile filifcrm, tortuous, 2 4f, bearing the single white fl. at or near the surface. 



ORDER CXXXVI. BURMANNIACEJS. 



Small annual herbs, with naked or scaly stems and scale-like tufted leaves. 

 Flowers perfect. Perianth tubular, 6-toothed, adherent. Stamens 3 or 0. 

 Capsule 1- or 3-celled. Seeds GO, minute, in a loose testa. 



1. APTERIA, 1ST. Perianth tube longer than the slender teeth, which 

 are alternately narrower. Caps, globular, 1-celled. (T) Apparently leafless. 



A. setacea N. Erect, very slender, 4 Gf, with remote subulate scales, and bearing 

 above 1 or 2 racemes ; flowers 3 4", purplish, distaut. Woods, Fla., and W. 



2. BURMANNIA, L. Perianth tube scarcely produced above the 

 ovary, often 3-winged below, limb with the 3 inner teeth much shorter. 

 Capsule prismatic, often 3-winged, 3-celled. Leafless. 



1 B. biflora L. Stems capillary, simple, 23', with scarcely perceptible bracts, and 



1 or 2 (rarely more) light-blue flowers, 23" long at top. Swamps, Va., and S. Oct. 



2 B. capitata (L). Stem setaceous, 6 8 X , simple, bearing at top a dense cluster of 



white flowers, and a few subulate bracts. Uplands, S. : less common. Sept. 



ORDER CXXXVII. ORCHIDACE^. ORCHIDS. 



Herbs perennial with fleshy roots, simple, entire, parallel-veined leaves. 

 Flowers very irregular, with an adherent, ringent periantfi of 6 parts. Sepals 

 3, usually colored. Petals 3, odd one (lowest by the twisting of the ovary), 

 called the lip, diverse in form from the others, sometimes lobed, often spur- 

 red. Stamens 3, gynandrous (consolidated with the style), some of them 

 abortive, pollen powdery or w r ax} r . Omry inferior, 1-celled,^ capsule 3-valved. 

 Seeds innumerable. Figs. 71, 105, 240, 247, b. 263, 291, 435. 



{ CYPRIPEDIli/E. Anthers, the 2 lateral fertile, the terminal pelaloid. . .(a) 



Lip a large, inflated, spurless sac. Petals and sepals spreading CYPRIFEDIUM. 1 



S OPHPvYDE/E, &c. Anthers, only the upper one fertile, 2-celled. . .( 



b Lip a large inflated sac, 2-spurred under the apex. Leaf 1 CALYPSO. ? 



b Lip produced behind into a spur, which is free from the ovary. . .(c) 

 b Lip spurless, or the spur adheres to the ovary (except in No. 13)... (J) 



c Anther fixed ; pollen-masses 2, club-shaped, in 2 separate cells c.. ORCHIS. 3 



c Anther lid-like, on the end of the stigma ; pollen-masses 4 TiPULAKU 4 



</ Plants brown and leafless, rarely with radical leaves... (e) 

 d Plants green and (except No. 10) furnished with leaves.. .(m) 



c Lip hooded, '. e., its margins involute. Perianth spreading. BLETIA. I 



e Lip concave, sessile, often with an adnate spur CORALLORHIZA. 6 



< Lip concave, raised on a chiw. Plant with 1 late leaf APLECTRUM. 7 



in Lip fiat. Flowers obscure, in racemes, nearly bractleas. . .(/i) 



m Lip Hat, expanded and lobed, tubercled at base. Flowers showy ONCIDJITM. I 



n Lip channelled, reflexed. Flowers whitish, in bracted spikes... (o) 

 m Lip bearded ei 3-lobed. Stamen lid like. Flowers showy., .(i) 



