Sparganium. TYPHACE^. 249 



2. Sparganium simplex, Huds. Smaller Bur-reed. 



Stem erect, simple or nearly so ; leaves triangular at the base, the sides flat ; stigma linear; 

 scales of the fertile heads not dilated at the summit. — Huds. ft. Angl. p. 401 ; Engl. hot. t. 

 745 ; Pursh, fl. 1. p. 34 ; Hook. fl. Bor.-Am. 2. p. 169 ; Kunth, enum. 3. p. 89. S. erectum, 

 p. Linn. sp. (ed. 2.) p. 1378. S. Americanum, Nutt. gen. 2. p. 203; Beck, hot. p. 380 ; 

 Darlingt. _fl. Cest. p. 520 ; Kunth, 1. c. 



var. ? angustifolium : leaves very narrow, floating ; scales of the fertile heads dilated at the 

 summit. S. angustifolium, Michx. fl. 2. p. 189 ; Bigel. fl. Bost. p. 339 ? S. natans, ;S. 

 angustifolium, Pursh, fl. 2. p. 34; Kunth, enum. 3. p. 89. S. natans. Beck, bat. p. 380; 

 Hook. fl. Bor.-Am. 2. p. 169 ? 



Stem 9-18 inches long, slender, mostly simple, but sometimes a little branched. Leaves 

 2-4 lines wide (narrowest in the floating variety), the lower ones considerably overtopping 

 the stem. Fertile heads usually 2, sometimes 3 or only one : scales scarious, oblong, in jS. 

 dilated at the summit. Style shorter than the narrow stigma. Fruit obovoid, acuminate with 

 the persistent style, the upper part solid and corky, the lower part indurated and containing 

 the seed. Embryo slender, in the axis of farinaceous albumen. 



Ponds, lakes, and slow-flowing streams, in the interior of the State, particularly in the 

 western counties. July - August. 



The plant which is considered by most of our botanists as S. simplex, is the S. Americanum 

 of Nuttall, but I have not been able to find characters that will distinguish ours from the 

 European species. I am also in doubt, for want of sufiicient materials, what dependence is 

 to be placed on the form of the floral scales as a mark of distinction. The floating form of 

 the plant seems to be a mere variety, but it may prove to be identical with S. natans of 

 Europe. It is not probable S. angustifolium of R. Brown is the same species as Michaux's. 



Order CIX. NAJADACE^. Juss. The Pondweed Tribe. 



Flowers usually diclinous, sometimes perfect, naked, or rarely furnished with a 

 regular perianth. Ovaries superior, 1-4 distinct : stigma simple or peltate. 

 Ovule solitary, suspended, orthotropous (very rarely erect and anatropous). 

 Fruit a little nut or indehiscent capsule. Seed with a very thin membrana- 

 ceous testa, destitute of albumen. — Aquatic plants, with simple cellular leaves 

 and sheathing spathe-like stipules. Flowers inconspicuous, often in spikes or 

 on a kind of spadix, sometimes axillary. 

 [Floka— Vol. 2.] 32 



