324 GRASS ORDER 



rowed spike ; leaves alternate, linear to lanceolate ; perennial herb with 



fleshy or tuberous roots. 



Stems 4-15 in. high; leaves linear or linear-oblance- 

 olate, 2-8 in. long; flowers 6-8 mm. long, white or 

 greenish-white, fragrant 5. stricta 



POALES GRASS ORDER 

 CYPERACEAE SEDGE FAMILY 



Sepals and petals none or represented by bristles or scales, stamens 1-3, 

 ovary 1-celled, style 2-3-cleft, fruit an achene ; flowers perfect or staminate 

 and pistillate, arranged in small dense clusters or spikelets, 1 or rarely 2 in 

 the axil of each bract or glume ; spikelets solitary or clustered, 1 -many-flow- 

 ered ; leaves narrow with closed sheaths ; grass-like or rush-like herbs, with 

 usually solid, triangular, cylindric or flattened stems. 



1. Flowers perfect, i. e., stamens and pistil in the 



axil of each scale 



a. Spikelets flattened, with the scales in 2 rows ; 



perianth bristles wanting Cyperus 



b. Spikelets not flattened; scales roundish, im- 



bricated all around ; perianth bristles usu- 

 ally present 



(1) Perianth bristles 1-many ; stamens usually 3 



(a) Bristles 1-12, usually less than 1 cm. 



long 



x. Leaves usually present; base of style 

 enlarged or narrow, falling away from 

 the achene Scirpus 



y. Leaves reduced to a single sheath at 

 base; base of style persisting on the 

 achene as a tubercle Heleocharis 



(b) Bristles usually many, 1-3 cm. long, 



giving the spikelets a cottony ap- 

 pearance Eriophorum 



(2) Perianth bristles wanting; stamen 1 Hemicarpi-ia 



2. Flowers staminate or pistillate, in the same or 



in different spikelets 



a. Achene enclosed in a sack or perigynium Carex 



b. Achene without a perigynium Elyna 



