496 HYDROCHARIDACE^. (fROG'S-BIT FAMILY.) 



by the prolonged calyx-tube, which varies in length according to the depth oi 

 the water. (Name from eAc«JS?7s, mar shy.) 



1. E. Canadensis, Michx. Leaves in 3's or 4's, or the lower opposite, 

 varying from linear to oval-oblong, minutely serrulate ; stamens 9 in the sterile 

 flowers, 3 or 6 almost sessile anthers in the fertile. (Anacharis CanadensiSi 

 Planchon.) — Slow streams and ponds, common. July. 



2. VALLISNERIA, L. Tape-grass. Eel-grass. 



Flowers strictly dioecious ; the sterile numerous and crowded in a head on a 

 conical receptacle, enclosed in an ovate at length 3-valved spathe which is borne 

 on a very short scape; stamens mostly 3. Fertile flowers solitary .and sessile 

 in a tubular spathe upon an exceedingly lengthened scape. Perianth (calyx) 

 3-parted in the sterile flowers ; in the fertile with a linear tube coherent with 

 the 1-celled ovary, but not extended beyond it, 3-lobed (the lobes obovate) ; 

 also 3 linear small petals. Stigmas 3, large, nearly sessile, 2-lobed. Ovules 

 very numerous, scattered over the walls, orthotropous. Fruit elongated, cylin- 

 drical, berry-like. — Stemless plants, with long linear grass-like leaves, wholly 

 submerged. The stamiuate clusters being confined to the bottom by the short- 

 ness of the scape, the flower-buds themselves break from their short pedicels 

 and float on the surface, where they shed their pollen around the fertile flow- 

 ers, which are raised to the surface by sudden growth at the same time ; after- 

 wards the thread-form scapes (2-4 feet long) coil up spirally, drawing the fruit 

 underwater to ripen. (Named for Ant. Vallisneri, an early Italian botanist.) 



1. V. spiralis, L. Leavesliuear, thin, long and ribbon-like (l -6° long), 

 obscurely serrulate, obtuse, somewhat nerved and netted-veined. — Common in 

 slow waters, N. Eng. to Fla., west to Minn, and Tex. 



3. LIMNOBIUM, Richard. American Frog's-bit. 



Flowers dioecious, (or monoecious ?) from sessile or somewhat peduncled 

 spathes ; the sterile spathe 1 -leaved, producing about 3 long-pedicelled flowers ; 

 the fertile 2-leaved, with a single short-pedicelled flower. Calyx 3-parted or 

 cleft ; sepals oblong-oval. Petals 3, oblong-linear. Filaments entirely united 

 in a central solid column, bearing 6-12 linear anthers at unequal heights; 

 there are 3-6 awl-shaped rudiments of stamens in the fertile flowers. Ovary 

 6 - 9-celled, with as many placentee in the axis, forming an ovoid many-seeded 

 berry in fruit ; stigmas as many as the cells, but 2-parted, awl-shaped. — A 

 stemless perennial herb, floating in stagnant water, proliferous by runners, 

 with long-petioled and round-heart-shaped leaves, which are spongy-reticulated 

 and purplish underneath ; rootlets slender, hairy. Sterile flowers rather small ; 

 the fertile larger; peduncle nodding in fruit. Petals Avhite ? (Name from 

 \ifxv6fiios, living in pools.) 



1. L. Spongia, Richard. Leaves 1 - 2' long, faintly 5-nerved ; peduncle 

 of sterile flower about 3' long and filiform, of the fertile only 1' long and stout. 

 — Stagnant water, N. J. to Fla. ; also L. Ontario, 111., and Mo. 



Order 109. BTJKMANNIACE^. (Burmannia Family.) 



Small annual herbs, often with minute and scale-like leaves, or those at the 

 root grass-like ; the Jiowers perfect^ with a Q-cleft corolla-like perianth, the 



