TYPHACEiE. (CAT-TAIL FAMILY.) 481 



2. SPARGANIUM, Tourn. ■' Bur-reed. 



Flowers collected in separate dense and spherical lcafy-bractcd heads, which 

 are scattered along the summit of* the stem; the upper ones sterile, consisting 

 merely of stamens, with minute scales irregularly interposed; the lower or fer- 

 tile larger, consisting of numerous sessile pistils, each surrounded by 3 -6 scales 

 much like a calyx. Fruit wedge-shaped or club-shaped. — Itootstocks creeping 

 and stoloniferous : roots fibrous. Stems simple or branching, sheathed below 

 by the base of the linear leaves. Flowering through the summer. (Name from 

 o-irupyavov, ajitlet, from the ribbon-like leaves.) 



* Erect, icith branched inflorescence of numerous heads: pistil as long as the surround- 



ing truncate scales, attenuated into a short style bearing one or often two elongated 

 stigmas: nuts sessile, wedge-shaped, angular: leaves for the greater part flat and 

 merely keeled, the base triangular with concave sides. 



1. S. eurycarpum, Engelm. Fruit many-angled (3i"-4"long) when 

 fully ripe, with a broad and depressed or retuse summit (2£" -3^" wide) ab- 

 ruptly tipped in the centre ; fruit-heads 1' wide. (S. ramosum, in part, of most 

 American botanists.) — Borders of ponds, lakes, and rivers, from New England 

 and Pennsylvania northward and westward. — Stems stout, 2° -4° high ; heads 

 2 to 6 or more : the largest species known. 



(S. raji6sum, Hudson, of Europe, has not yet been found on this continent : 

 it is distinguished by smaller heads, and smaller, few-angled, usually 1 -seeded 

 fruit, with a conical and long-pointed summit.) 



* * Erect or rarely floating, with simple (or rarely branched) inflorescence of numer- 



ous heads ; the conspicuous style longer than the spatulate denticulate scales: stig- 

 mas always single, linear or oblong: nuts attenuated at both ends, and with a 

 stalked base, nearly terete: stems rather slender : leaves (unless floating) triangu- 

 lar with flat sides in the lower half 



2. S. simplex, Hudson, genuinum. Erect (9'- 15' high), slender; in- 

 florescence simple, the lower heads supra-axillary, sessile or commonly pedun- 

 cled (""-8" wide); stigma linear, equal to the style; fruit more or less con- 

 tracted in the middle. — New England and northward. (Eu.) 



Var. Nuttallii. Like the last or type, but heads axillary ; stigma linear- 

 oblong, shorter than the style; fruit less contracted. (S. Americanum, Nutt.) 

 — From Pennsylvania and New England northward and northwestward. — In- 

 florescence rarely branched; heads 8" -9" wide. 



Var. androcladum. Stouter (U°-3° high); inflorescence branched be- 

 low; branches bearing numerous sterile (rarely also 1 or even 2 fertile) heads; 

 stigma linear, as long as the style; fruit larger, not contracted, long-tapei'ing 

 upwards and downwards. (S. ramosum. in part, of American authors.) — From 

 New England southward and especially westward. — Heads 10"- 12" wide. 



Var. fltlitans. Leaves floating ; inflorescence branched ; branches bearing 

 fertile heads below ; stigma oval, shorter than the style ; fruit somewhat con- 

 tracted and with a short stipe. (S. fluitans, Fries.) — Ponds at the base of the 

 "White Mountains, Oakes. — Heads G"- 7" wide. (Eu.) 



Var. angustifblium. Leaves floating, longer and narrower than in the 

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