CYPERACE^E. 311 



tary, each in the axil of a glume-like bract. Perianth wanting, or 

 else reduced to mere bristles. Stamens usually 3, sometimes 2, 

 or i. Styles 2-3, more or less united. Fruit an achenium. 



C Flowers with bristles Dulichium. 

 ' Flowers in regular spikelets \ 



Flowers without bristles Cyperus. 



Achenium with tubercle at apex Eleocharis. 



regular 

 t. spikelets. 



Bristles 



^ ked at apex- 



(_Not cottony Scirpus. 



Bristles none Fimbristylis, 



{ Bristles present Rhynchospora, 



Flowers imperfect -j f Achenium in sac Carex. 



| Bristles nons -J 

 [ I, No sac Cladium, 



I. Cyperus. Spikelets few, many-flowsred, in loose or dense clus- 

 ters. Glumes arranged in 2 rows, decurrent at base. Stamens 1-3, 

 usually three. Style 2-3-cleft. Achenium lenticular or triangular. 

 Culm triangular, with 1-3 leaves at summit, forming an involucre to 

 the umbel. 



1. C. DIANDRUS (Brown Sedge). Culm slender, usually decumbent ; 

 spikelets flat, oblong-lanceolate, acutish, i4-2c-flowered, more or less in fas- 

 cicles forming an umbel with 2-4 very short, sometimes unequal rays ; glumes 

 oblong, brown on the margin ; stamens 2. Stem 6'-io' long. August- 

 September. 



2. C. STRIGOSUS (Bulbous Sedge). Culm erect, leafy, tuberous at base ; 

 leaves broad-linear ; umbel simple or decompound ; spikelets narrow-linear, 

 flat and few-flowered, at length reflexed, on spikes forming an umbel ; scales 

 oblong-lanceolate, yellowish ; stamens 3 ; achenium narrow-oblong. In wet 

 grounds, 1-2 feet high. August. 



2. Dulichium. Spikelets linear, compressed, arranged in 2 rows, 

 on solitary, axillary peduncles. Glumes arranged in 2 rows. Perianth 

 reduced to bristles. Stamens 3. Style 2-cleft above, the lower portion 

 persistent, forming a beak to the compressed achenium. 



D. SPATHACEUM (Sheathed Sedge). Culm erect, simple, leafy, sheathed 

 below ; leaves alternate, linear, flat, short, arranged on the stem in 3 rows ; 

 spikes proceeding from the sheaths, consisting of 8-12 linear-lanceolate spike- 

 lets, in 2 rows ; spikelets s-g-flowered, rather long. Along rivers and bor- 

 ders of ponds, 1-2 feet high. August. 



3. Eleocharis. Spikes single, terminal. Glumes imbricated all 

 round without much order. Perianth reduced to 3-12, mostly 6, rigid, 

 persistent bristles. Stamens 3. Style 2-3-cleft, bulbous and persistent 

 at base. Culms leafless, simple. 



15 



