ORCHIDACEAE (ORCHID FAMILY) 69 



SPIRANTHES (LADIES' TRESSES) 



Erect; roots fleshy-fibrous or tuberous. Stem leafy. Flowers small. 

 Upper sepals cohering to the petals. Lip dilated, spreading. Pollen 

 masses i pair. In wet places. (Gk. speira = a coil, anthos = a flower ; 

 referring to the spirally twisted racemes.) 



A. Perianth about 8 mm. long; lip much dilated at apex, basal swellings small. 



W. C. E. S. romanzoffiana 



AA. Perianth about 6 mm. long; lip little dilated at apex, basal swellings large. 



W. C. E. S. porrifolia 



LISTERA (TWAYBLADE) 



Small. Leaves nearly opposite, sessile. Flowers in a terminal raceme, 

 spurless, greenish or madder-purple. Sepals and petals nearly alike, free. 

 Lip longer than the sepals, 2-lobed or 2-cleft at summit. Pollen masses 

 i pair. Stigma with a somewhat rounded beak. In dense damp woods. 

 (Honor of M. Lister, an English naturalist.) 



A. Raceme glabrous or nearly so; lip 2-cleft to about the middle, about 4-5 mm. long. 



W. C. E. L. cordata 



AA. Raceme densely glandular-pubescent; lip 2-lobed or merely retuse, the divisions 



less than the distance to the base. 



B. Leaves rounded to truncate at base; petals 3-4 mm. long; lip 5 mm. long; 



capsule ovoid. W. C. L. caurina 



BB. Leaves cordate to reniform at base; petals 4-6 mm. long; lip 9 mm. long; 



capsule obovoid. C. E. L. convallarioides 



CORALLORHIZA (CORAL ROOT) 



Saprophytes or root parasites ; roots coral-like, branched ; stems scapose, 

 simple. Leaves sheathlike, membranous, white to red, without green. 

 Flowers in a terminal raceme, more or less showy. Lateral sepals united 

 at base into a short spur or a swelling. Petals about as long as the sepals, 

 i~3-veined ; lip i-3-ridged ; pollen masses 2 pairs. In dense woods. 

 (Gk. korallion = coral, riza = a root; on account of the knotted, fungus- 

 covered roots.) 



A. Sepals and petals 6-8 mm. long; spur present. 



B. Sepals and petals 3-veined; spur prominent; capsule oblong-cylindric. 

 C. Lip crenulate, with 2 lobes at base; spur wholly adnate to the ovary. W. C. E. 



C. multi flora 



CC. Lip not crenulate, with or without 2 basal lobes; spur free for its apical half. 



W. C. C. mertensiana 



BB. Sepals and petals i-veined; spur very short, wholly adnate to the ovary; lip 



2-toothed or 2-lobed above the base; capsule oblong-elliptical. E. C. corallorhiza 



AA. Sepals and petals 12-17 mm. long, 3-veined; spur none. W. E. C. striata 



