614 Rydherg : The American Species of 



Plant 5-8 dm. high ; spur 10-14 mm. long ; lip 7-9 mm. 



Dilated portion rf the lip oval ; spur almost 7^ longer than the 



lip. 



15. Z. Thurbei'i. 



Dilated portion of the lip decidedly rhombic ; spur scarcely 

 longer than the lip. 1 6. Z. leucostachys. 



Spur clavate at the apex. 



Leaves lanceolate or oblanceolate ; stem tall and stout; lip decid- 

 edly rhombic at the base. 16. Z. leucostachys robmta. 

 Leaves narrowly linear; stem slender ; lip not rhombic at the base. 



17. Z. gra mini folia. 

 Lip linear, i. e. 9 not at all dilated at the base. 



Spur usually shorter than the lip. 



Flowers purplish or greenish ; spur very short and decidedly saccate. 



I. Z. strict a. 

 Flowers white ; spur almost equalling the lip. (Convallariaefoliak. ) 

 Spur clavate. 18. Z. gracilis. 



Spur filiform 



19. Z. convallaria folia. 



Spur much exceeding the lip ; flowers greenish or purplish. 



Connective narrow; spur almost twice as long as the lip. (A RIZON 



ICAE.) 



Connective broad. 



20. Z. Arizonica. 



Leaves elongated, lanceolate or linear; spur 8-10 mm. long. 



(Sparsiflorae.) 



Spike comparatively dense. 21. Z. ensi folia. 



Spike very lax. 



Lip about 6 mm. long; spur about 8 mm., somewhat 



clavate. 22. Z. laxijlora. 



Lip about 8 mm. long; spur over 10 mm., filiform. 



23. Z. spar si flora. 

 Leaves very short, ovate ; spur almost 1.5 cm. long. (Brevi- 

 FOLIAE.) 24. Z. brevifolia. 



§ 



usually dense, except in the first species ; flowers small, greenish 

 or tinged with purple, especially the petals ; spur less than twice 

 as long as the lip ; lip except in L. stricta lanceolate, i. c, some, 

 what dilated at the base but not at all rhombic ; connective nar- 

 row and anther-sacs close together. 



1. LlMNORCHiS stricta (Lindl.) Rydb. Mem. N. Y. Bot. 



Garden I : 105. 1900 



Ptatanthera stricta Lindl. Gen. & Sp. Orchid. PL 288. 1835-9 I 

 Habcnaria gracilis Wats. Proc. Am. Acad. 11 : 277. 1876 ; Habc- 



rborea Rothrock, Wheeler's Rep. 4 : 265. 1878 ; Habc- 



hyp, 



Erythea, 3:49. 1895; Hab 



Ryd. Bull. Torr. Club, 24: 189. 1897; Platanthcra gracilis 



Krae 



1899. Not Lindl. 



