TTPHACKiE. (cat-tail FAMILY.) 481 



2. SPABGANIUM, Tourn. Bub-beed. 



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. — Eootstocks creeping 

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

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

 inrapyavov, a fillet, from the ribbon-like leaves.) 



* Erect, with branched infiorescence 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. enryo&rpum, Engelm. Fruit many-angled (3j"-4"long) when 

 fully ripe, with a broad and depressed or retuse summit (2J"-3J" 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° - i" high ; heads 

 2 to 6 or more : the largest species known. 



(S. ram6sum, Hudson, of Europe, has not yet been found on this continent i 

 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 spatidate denticulate scales : stig- 

 mas a/ways 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 (7" -8" wide); stigma linear, equal to the style; fruit more or less con- 

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



Var. ]S"uttd.llii. 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 northwestwai'd. — In- 

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



Var. andrdoladum. Stouter (1|°- 3° high); inflorescence branched be-- 

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

 atigma linear, as long as the style ; fruit larger, not contracted, long-tapering 

 upwards and downwards. (S. ramosum, in pai-t, of American authors.) — From 

 New England southwai'd and especially westward. — Heads 10"- 12" wide. 



Var. fltlitaus. 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, Ouies. — Heads 6" -7" wide. (Eu.) 



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

 31 



