ALISMACEAE. 7 



Family 1. ALISMACEAE DC. 

 WATER-PLANTAIN FAMILY. 



Aquatic or marsh herbs, mostly glabrous, with fibrous roots, scapose 

 stems and basal long-petioled sheathing leaves. Inflorescence racemose or 

 paniculate. Flowers pedicelled, the pedicels verticillate and subtended by 

 bracts. Receptacle flat or convex. Sepals 3, persistent. Petals 3, larger, 

 deciduous, imbricated in the bud. Stamens 6 or more; anthers 2-celled, 

 extrorse or dehiscing by lateral slits. Ovaries 1-celled, usually with a single 

 ovule in each cell. Carpels becoming achenes in fruit in our species. Seeds 

 uncinate-curved. Embryo horseshoe-shaped. Endosperm none. Latex- 

 tubes are found in all the species, according to Micheli. About 13 genera 

 and 70 species, of wide distribution in fresh water swamps and streams. 



Flowers perfect. 1. Echinodorus. 



Flowers monoecious or dioecious. 2. Sagittaria. 



1. ECHINODORUS Kichard; Engelm. in A. Gray, Man. 460. 1848. 



Perennial or annual herbs with long-petioled elliptic, ovate or lanceolate, 

 often cordate or sagittate leaves, 3-9-ribbecl and mostly punctate with dots or 

 lines. Scapes often longer than the leaves; inflorescence racemose or panicu- 

 late, the flowers verticillate, each verticil with 3 outer bracts and numerous 

 inner bracteoles. Flowers perfect; sepals 3, distinct, persistent; petals white, 

 deciduous; receptacle large, convex or globose; stamens 12-30; ovaries numer- 

 ous; style obliquely apical, persistent; stigma simple. Fruit achenes, more or 

 less compressed, coriaceous, ribbed and beaked, forming spinose heads. [Greek, 

 in allusion to the spinose heads of fruit.] About 14 species, mostly natives of 

 America. Type species: Eclnnodorus restrains Engelm. 



1. Echinodorus cordifolius (L.) Griseb. Kar. 109. 1857. 



Alisma cordifolia L. Sp. PI. 343. 1753. 



Ecliinodorus rostratus Engelm. in A. Gray, Man. 460. 1848. 



Leaves variable in form, often broadly ovate, obtuse, cordate at the base, 

 15-20 cm. long and wide, but in smaller plants sometimes nearly lanceolate, 

 acute at each end and but 2-5 cm. long; petioles angular, striate ; scapes 1 or 

 more, erect, 12-40 cm. tall; flowers 3-6 in the verticils; pedicels erect after 

 flowering; sep'als shorter than the heads; petals 4-6 mm. long; stamens often 

 12 ; styles longer than the ovary ; fruiting heads bur-like, 4-6 mm. in diameter ; 

 achenes about 3 mm. long, narrowly obovate or falcate, 6-8'-ribbed ; beak apical, 

 oblique, about one-half the length of the achene. 



In sink-holes and fresh water swamps. Andros, Cat Island, Watling's Island, 

 Crooked Island, Acklin's Island, Fortune Island, Great Exuma, Grand Turk : South- 

 eastern United States ; Jamaica ; Cuba to St. Thomas and Barbadoes. BUR-HEAD. 



2. SAGITTARIA L, Sp. PI. 993. 1753. 



Perennials, mostly with tuber-bearing or nodose rootstocks, basal long- 

 petioled nerved leaves, the nerves connected by numerous veinlets, and erect, 

 decumbent or floating scapes, or the leaves reduced to bladeless phyllodes. 

 Flowers monoecious or dioecious, borne near the summits of the scapes in verticils 

 of 3 's, pedicelled, the staminate usually uppermost. Verticils 3-bracted. Sepals 



