MICH-IGAN ACADEMY OF SCIENCE. 



243 



C. Perianth less than 15 mm. across; flowers 

 greenish-white to whitish, or dull yellow. 

 Leaves several, basal, often veined 



with white ; flowers in bracted spikes . 19. Peramium. 

 Leaves only 1 or 2 (visible after anthesis 

 in A'plectrum) . 



Flowers dull yellow in a short raceme ; 

 plant with globular corms con- 

 nected by a slender root-stock. ... 23. 



Flowers greenish-white to whitish; 

 petals filiform or linear. 

 Leaf solitary, sheathing the stem . . 20. 

 Leaves 2. 



Leaves basal, lanceolate to ovate ; 

 lip 5-12 mm. long; plants 



with solid bulbs 21. Liparis. 



Leaves in a pair near the middle 

 of the stem ; flowers small (less 

 than 4 mm. long); no bulbs; 

 roots stringy 18. Ophrys. 



Apleclrum hye- 

 male. 



Malaxis. 



1. CYPRIPEDIUM L. Ladies' Slipper. Moccasin Flower. 



The three sepals separate; stem 1-flowered ; flowers small (1.5- 



2 cm. long) 1. C. arielinum. 



The three sepals more or less united. 



Sepals and petals shorter than the lip, which is crimson- 

 magenta in front 2. C. reginae. 



Sepals and petals equaling or longer than the lip. 



Lip white, small (18-20 mm. long) 3. C. candidum. 



Lip yellow, large. 



Lip 2-3 cm. long, golden-yellow; plant of boggy places . 4. C. parviflorum. 

 Lip 3.5-5 cm. long, lig^t yellow; mostly in woods. . . . 4a. C. parviflorum var. 



pubescens. 



Cypripedium arietinum R. Br. (ram's head). 

 Ram's Head Ladics'-slipper. 



Rare in the Lower Peninsula. Damp woods and swamps. May, June. 

 Lip "prolonged at the apex into a long, blunt spur, somewhat distorted 

 at the upper end, which resembles a ram's heiid, whence the specific name". 



