466 



NATURAL HISTORY OF PLANTS. 



sented by a single species, S. cernuus* (figs. 498, 499), a perennial 

 herb from the marshes of North America, often cultivated in our 

 botanical gardens. Its flowers are small and numerous, whitish, 

 hermaphrodite, regular, and achlamydeous. On the convex recep- 

 tacle are inserted usually six stamens 2 below a central gynseceum. 



Saururus ceriums. 





Fig. 498. 

 Long. sect, of flower (i). 



Fig. 499. 

 Diagram. 



Each stamen consists of a free elongated filament, and a basifixed 

 introrse two-celled anther of longitudinal dehiscence. The superior 

 gyna?ceum usually consists of four free carpels, two of which are 

 lateral (fig. 499) ; each has a one-celled ovary, tapering above into a 

 style, the apex of which is stigmatiferous internally. In the 

 ventral angle of the ovary, which is not perfectly closed, is a parietal 

 two-lipped placenta, each lip bearing one or two obliquely ascending 

 orthotropous ovules with their micropyles superior. 3 In the fruit 

 each ovary becomes a slightly fleshy, one-seeded berry. The seed, 

 formed as in the Peppers, contains beneath its coat two albumens ; 

 one is large and farinaceous ; the other, surmounting it, is much 

 smaller and fleshy, surrounded by the embryo-sac, and envelopes a 

 little embryo with a short superior radicle and thick cotyledons. 

 S. cernuus has a rhizome, from which spring the herbaceous annual 



1 L., Spec, ed. 2, 489. — Rich., in Michx. Fl. 

 Bor.-Ar.ier., i. 218. — Nutt., Gen., i. 240. — 

 Toee. & Gkay, Fl. N.-Amer., i. 381. — A. Geat, 

 Man., ed. 5, 427.— Chapm., Fl. S. Unit.-St., 

 398. — 8. hicidiis Don, Hort. Cant., 66. — Jacq. 

 F., Eel. Amer., 29, t. 18. — Serpentaria repens 

 PlUKN., Almag., 343.— iS. foliis profunde cor- 



dalis L., Hort. Cliff., 139. — Mattuschlcia 

 aquatica Gmel., Syst., 589. 



2 In this case one stands anterior, one posterior, 

 and two more on either side of the flower. The 

 upper flowers have often a smaller number, or in 

 our cultivated specimens from seven to ten. 

 . 3 They have two coats. 



