ALISMACE^K. (WATER-PLANTAIN FAMILY.) 437 



SUBORDER I. JUNCAGIWE^E. THE ARROW-GRASS FAMILY. 



1. TRIGL.6CHIN, L. ARROW-GRASS. 



Sepals and petals nearly alike (greenish), ovate, concave, deciduous. Sta- 

 mens 6 : anthers oval, on very short filaments. Pistils united into a 3-6-celled 

 compound ovary : stigmas sessile : ovules solitary. Pod splitting when ripe 

 into 3-6 carpels, which separate from a central axis. Leaves rush-like, fleshy, 

 sheathing the base of the wand-like naked and jointless scape. Flowers small, 

 in a spiked raceme, bractless. (Name composed of rpels, three, and y\<a\lv^ 

 pdint, from the three points of the ripe fruit in No. 1.) 



1. T. palustre, L. Scape (6' -18' high) and leaves slender ; fruit linear- 

 dub-shaped ; the 3 carpels when ripe separating from below upwards from the tri- 

 angular axis, and awl-pointed at the base. 1J. Marshes, both fresh and brack- 

 ish, New York to 111., and northward. Aug. (Eu.) 



2. T. mil! itillllllll, L. Scape (12' -20' high) and leaves thiclcish, fleshy , 

 fruit ovate or oblong, acutish, of 6 or rarely 5 carpels which are rounded at the base 

 and slightly grooved on the back ; the edges acute. 1|. Salt marshes along the 

 coast ; salt springs, Salina, New York ; shore of the Great Lakes, and north- 

 ward. Var. ELATUM (T. elatum, Nutt.} grows in cold and fresh bogs, from 

 W. New York to Wisconsin, often 2 high, and has the angles of the carpels 

 sharper, or almost winged. (Eu.) 



2. SCIIEUCHZERIA, L. SCHEUCHZERIA. 



Sepals and petals oblong, spreading, nearly alike (greenish-yellow), but the 

 latter narrower, persistent. Stamens 6 : anthers linear. Ovaries 3, globular, 

 slightly united at the base, 2-3-ovuled, bearing flat sessile stigmas, in fruit 

 forming 3 diverging and inflated 1 - 2-seeded pods, opening along the inside. 

 A low bog-herb, with a creeping jointed rootstock, tapering into the ascending 

 simple stem, which is zigzag, partly sheathed by the bases of the grass-like con- 

 duplicate leaves, terminated by a loose raceme of a few flowers, with sheathing 

 bracts. (Named in honor of the two brothers Scheuchzer, distinguished Swiss 

 botanists.) 



1. S. palustris, L. Peat-bogs, New England to Penn., Illinois, and 

 north ward ; rather rare. July. (Eu.) 



SUBORDER II. AL.ISME2E. THE WATER-PLANTAIN FAMILY. 



3. ALISMA, L. WATER-PLANTAIN. 



Flowers perfect. Petals involute in the bud. Stamens definite, mostly 6. 

 Ovaries many in a simple circle on a flattened receptacle, forming flattened cori- 

 aceous achenia, which are dilated and 2 - 3-keeled on the back. Boots fibrous. 

 Leaves all from the root, several-ribbed, with connected veinlets. Scape with 

 whorlcd panicled branches. Flowers small, white or pale rose-color /The 

 Greek name ; of uncertain derivation.) 



