TYPHACE^E. (CAT-TAIL FAMILY.) 481 



2. SPARGANIUM, Tourn. BUR-REED. 



Flowers collected in separate dense and spherical leafy-bracted 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. Rootstocks creeping 

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

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

 <r7rdpyavov, a fillet, from the ribbon-like leaves.) By DR. G. ENGELMANN. 



* Erect, with 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 keeted, the base triangular with concave sides. 



1. S. eiirycarpum, Engelm. Fruit many-angled (3"-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. RAM6suM, 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, GENU!NUM. Erect (9' -15' high), slender; in- 

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

 cled (7" -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 (l^-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-tapering 

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

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



Var. fliiitans. 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 6" -7" wide. (Eu.) 



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

 31 



