ORCHIDACEAE. 67 



91. OLSYNIUM. 



Very similar to Sisyrinchium but the filaments united only at 

 the base and the flowers never blue. 



Olsynium grandiflorum (Dougl.) Raf. Stems mostly solitary, 15-30 cm. 

 tall, compressed; roots fascicled, stout; leaf-blades 5-10 cm. long, erect, shorter 

 than the sheaths; flowers 1-4, the pedicels shorter than the largest bract; 

 perianth-segments reddish-purple, broadly lanceolate, acuminate, 15-18 mm. 

 long; filaments broad at the base, shorter than the 3-cleft style. Very common. 



Family 23. ORCHIDACEAE. ORCHID FAMILY. 



Perennial herbs, with corms, bulbs or tubers; leaves entire, 

 sheathing, sometimes reduced to scales; flowers perfect, irregular, 

 bracted, solitary, spiked or racemed; perianth superior, of 6 

 segments, the three outer (sepals') alike or nearly so; two of the 

 inner ones (petals') lateral, alike; the third inner one (lip) dis- 

 similar, often markedly so, usually larger, often spurred, some- 

 times inferior by the twisting of the ovary or pedicel; stamens 

 variously united with the style into an unsymmetrical column; 

 anther one (sometimes two); pollen more or less coherent into 

 masses (pollinia) ; ovary inferior, usually long and twisted, 

 3-angled, 1-celled; ovules numerous on three parietal placentae; 

 seeds numerous ; endosperm none. 



Perfect anthers 2; lip large, sac-like. 92. CYPRIPEDIUM, 68,. 



Perfect anther 1. 



Plant saprophytic, without green herbage. 



Flowers spurred, reddish or white. 93. CORALLORHIZA, 68". 



Flowers spurless, white. 94. CEPHALANTHERA, 69\ 



Plants with ordinary green herbage. 



Flower and leaf solitary; plant bulbous. 95. CYTHEREA, 69. 



Flowers several-many in racemes. 



Leaves only two. 96. OPHRYS 69. 



Leaves more than two. 



Flowers each with a distinct spur. 

 Leaves several, cauline, gradu- 

 ally reduced upwards. 97. LIMNORCHIS, 70. 

 Leaves two, basal; cauline re- 

 duced to bracts. 

 Lateral sepals adnate to the 



base of the lip. 98. PIPERIA, 70. 



Lateral sepals free. 99. LYSIAS, 71. 



Flowers spurless, the lip at most 



saccate. 



Lip with 2 callosities at base; 

 flowers spirally arranged in a 

 dense spike. 100. IBIDIUM, 71. 



Lip without basal callosities. 



Leaves white-reticulated. 101. PERAMIUM, 71. 

 Leaves green. 102. EPIPACTIS, 72. 



