ORDER 137 ORCHID ACE^). 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 segm. and 3 bifid stig. Fr. cylindrical, 



00 - seeded. H Xff Fertile flowers on long spiral scapes. July, Aug. 



V. npiralis L. Lvs. 1 2f long, obtuse, |' wide, scapes of the sterile plants short, of 

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



ORDER CXXXVI. BURMANNIACE.E. 



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

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

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



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

 are alternately narrower. Caps, globular, 1-celled. @ Apparently leafless. 

 A. setacea N. Erect, very slender, 4 6f, with remote subulate scales, and bearing 



above 1 or 2 racemes ; flowers 34", purplish, distant. 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 IS. biflora L. Stems capillary, simple, 23', with scarcely perceptible bracts, and 



1 or 2 (rarely more) light-blue flowers, 2 3" long at top. Swamps, Va., and S. Oct. 



2 B. capitata (L). Stem setaceous, 6 S 7 , simple, bearing at top a dense cluster of 



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



ORDER CXXXYII. ORCHIDACE^E. ORCHIDS. 



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

 Flowers very irregular, with an adherent, ringent perianth 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 powdeiy or waxy. Ovary inferior, 1-celled, capsule 3-valved. 

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



S CYPRIPEDIE^. Anthers, the 2 lateral fertile, the terminal petaloid. . .(a) 



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



$ OPHRYDE^E, Ac. Anthers, only the upper one fertile, 2-celled. . .(b) 



b Lip a large inflated sac, 2-spurred under the apex. Leaf 1 C ALTPSO. t 



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). . .(d) 



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



c Anther lid-like, on the end of the stigma ; pollen-masses 4 . .TIPULARIA * 



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

 d Plants green and (except No. 16) furnished with leaves... (m) 



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



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



f Lip concave, raised on a claw. Plant with 1 late leaf APLECTBDM. 7 



m Lip flat. Flowers obscure, in racemes, nearly bractless. . .() 



m Lip flat, expanded and lobed, tubercled at base. Flowers showy OwcimnM. 8 



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

 m Lip bearded or 3-lobed. Stamen lid-like. Flowers showy. . .(x) 



