30 JUNCAGINACEAP: (ARROW GRASS FAMILY) 



Mexico and southern Colorado northward, and in both the Pacific and the 

 Atlantic States. 



4. NAIAS L. 



Slender branching herbs, growing under water, with opposite and linear 

 leaves somewhat crowded into whorls, spinulose-toothed, sessile and dilated 

 at base. Flowers very small, solitary, but often clustered in the axils; dioecious 

 or monoecious, axillary, solitary and sessile; the sterile consisting of a single 

 stamen inclosed in a little membranous spathe; anther at first nearly sessile, 

 the filament at length elongated. Fertile flowers consisting of a single ovary 

 tapering into a short style; stigmas 2-4, awl-shaj^d. Fruit a little seed-like 

 nutlet, inclosed in a loose and separable membranous epicarp. 



Leaves acuminate; seeds with 30-50 rows of faint reticulations . 1. N. flexilis. 

 Leaves abruptly acute; seeds with 16-20 rows of conspicuous reticu- 

 lations . . . . . . . . . . . 2. N. guadalupensis. 



1. Naias flexilis (Willd.) Host. & Schmidt. Fl. Sed. 384. 1824. Stems very 

 slender: leaves linear, becoming acuminate, minutely serrulate, 1-3 cm. long; 

 sheaths obliquely rounded, with 5-10 teeth on each edge: dioecious: fruit 

 ellipsoid, about 3 mm. long, tipped with the long style and the 3 short stigmas: 

 seeds smooth and shining, sometimes faintly sculptured with 30-50 rows of 

 reticulations. Said to occur in most parts of North America. 



2. Naias guadalupensis (Spreng.) Morong, Mem. Torr. Club 3 2 : 60. 1893. 

 Very similar, but the stems long (3-6 dm.) and freely branched: leaves shorter, 

 the edges parallel, abruptly acute : fruit dull (not shining) and strongly marked 

 with 16-20 rows of reticulations which are transversely oblong. Widely 

 distributed but not common; Colorado to Florida and Oregon. 



13. JUNCAGINACEAE Engler & Prantl. ARROW GRASS 



FAMILY 



Rush-like plants growing in wet or marshy places, ours in saline soils. 

 Leaves rush-like or cylindrical. Flowers in simple spikes or racemes, perfect; 

 perianth segments 3-6; stamens 3-6. Ovaries 3-6, more or less united when 

 immature. Naiadaceae in part. 



1. TRIGLOCHIN L. ARROW GRASS 



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

 uous. Stamens 3-6; anthers oval, on very short filaments. Pistils united 

 into a 3-6-celled compound ovary; stigmas sessile; ovules solitary. Capsule 

 splitting when ripe into 3-6 carpels, which separate from a persistent central 

 axis. 



Carpels 6; fruit obtuse at base . . . . . . . 1. T. maritima. 



Carpels 3; fruit attenuate at base 2. T. palustris. 



1. Triglochin maritima L. Sp. PI. 339. 1753. Rather stout, 2-10 dm. 

 high: leaves shorter than the scape, 2-4 mm. broad: raceme usually crowded, 

 1-3 dm. long: flowers 2 mm. broad: fruit obtuse at base, 6-carpeled, 3-5 

 mm. long, and about equaling the pedicels. In saline places across the 

 continent. 



2. Triglochin palustris L. Sp. PI. 338. 1753. Slender, 1-3 dm. high: 

 leaves less than 2 mm. broad: flowers smaller: fruit attenuate at base, 3- 

 carpeled, 5-8 mm. long, exceeding the pedicels, separating from below up- 

 ward. From the Rocky Mountains eastward across the continent. . 



