496 HYDROCHARIDACE^. (FROG*S-BIT FAMILY.) 



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

 the water. (Name from eAeSSrjs, marshy.) 



1. E. Canad&nsis, 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 Canadensis, 

 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 staminate 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 

 under water to ripen. (Named for Ant. Vallisneri t an early Italian botanist.) 



1. V. spiralis, L. Leaves linear, thin, long and ribbon-like (1-6 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 placentae 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 white ? (Name from 

 \ifjivbfiios, living in pools.) 



1 . L. Sp6ngia, Richard. Leaves 1 - 2' long, faintly 5-nerved ; peduncle 

 of sterile flower about 3' long and filiform, of the fertile only T long and stout. 

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



ORDER 109. BURMANNIACE^E. (BURMANNIA FAMILY.) 



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

 root grass-like ; the flowers perfect, with a 6-cleft corolla-like perianth, the 



