ALISMACE^E. ( WATER-PLANTAIN FAMILY.) 491 



shaped. Leaves or some of them commonly furnished with a blade. 

 (Flowers perfect, monoecious, or sometimes dioecious.) 



3. Alisma. Flowers perfect, with definite, mostly 6 stamens. Carpels flattened, whorled. 



4. Kcliiiiodorus. Flowers perfect, with 6 -many stamens. Carpels capitate, ribbed. 



5. Sagittaria. Flowers monoecious, rarely dioecious, with indefinite, rarely few stamens. 



Carpels capitate, flattened, winged. 



1. TBIGLOCHIN, L. ARROW-GRASS. 



Sepals and petals much alike (greenish^, ovate, concave, deciduous. Stamens 

 3 - 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 persistent central axis. Perennials, 

 with rush-like, fleshy leaves, below sheathing the base of the wand-like naked 

 and jointless scape. Flowers small, in a spiked raceme, bractless. (Name 

 composed of rpels, three, and yXw^iV, point, from the three points of the ripe 

 fruit in No. 1 when dehiscent.) 



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

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

 triangular axis, awl-pointed at the base. Marshes, both fresh and brackish, New 

 York to Illinois, and northward. Aug. (Eu.) 



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

 fruit ouate or oblong, acutish, of ft or rarely 5 carpels which are rounded at the base 

 and sliyhtly grooved on the back; the edges acute. Salt marshes along the coast, 

 also salt springs in the interior, shore of the Great Lakes, and northward. 

 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. SCHEUCHZERIA, 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, and terminated by a loose raceme of a few flowers, with sheath- 

 ing bracts. (Named for John and John Jacob Scheuchzer, distinguished Swiss 

 botanists early in the 18th century.) 



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

 and northward. June, July. (Eu.) 



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. Roots fibrous. 



