5S. Eleocharis Re Bre. Spike Rush, 
Annual or perennial herbs, usually of muddy or moist ground, Stems 
S-angled or columnar, the leaves reduced to cylindrical sheaths at the 
very base, Spikelets solitary, terminal, ercct, many-flowered, ovate or 
cylindrical, not flattened, not subtended by an involucre, the scales 
spirally arranged, overlapping; perianth of several downwardly barbed 
bristles, sometimes wanting, Stamens 2+3, Style 2-cleft, the achenes 
being then biconvex, or 3-cleft, the achene being then 3-angled, Base of 
the style persistent upon the achene as a small tubercle, 
0 Stems 20-60 cm, tall, erect, gregarious but hardly tufted; 
4 perennial by stout rootstocks 
a Fertile scales obtuse; tubercle elongate-pyramidal 1, Ee palustris 
2 Fertile scales acutish; tubercle evenly triangular Ze He mamillata 
O Stems 20-30 cm, tall, erect.or ascending, tufted, vith 
fibrous roots, annuals or perennials by threadlike 
ps 
@ Tufts 2-8 om, tall; spikes 2,5-5 mm, long; styles 
6 3-cleft 
4 Annual without stolons | S, 8, della 
«| Perennial with numerous slender whiplike stolons 4, E, acicularis 
Tufts 15-30 om, tall; spikes mostly 8-12 mm, long; 
styles 2-cleft 
Spikes 2 1/2-3 times as long as broad, ovate-cylindrical; 
bristles shorter than the achene Se EB. Engelmannii 
Spikes twice as long as broad, ovete, obtuse; 
bristles longer than the achene Ge Ke obtusa 
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