36 JUNCAGINACEAE (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-shaped. Fruit a little seed-hke 

 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. guadalupensia. 



1. Naias flexiUs (Willd.) Rost. & 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^: 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. JUNCAGmACEAE Engler & Prantl. Arrow Grass 



Family 



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

 Leaves rush-like or cyUndrical. 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 sfissile; ovules solitary. Capsule 

 splitting when ripe into 3-6 carpels, which separate from a per,sistent 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. 1763. 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 obtiise at base, 6-carpeled, 3-5 

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

 continent. 



2. Triglochin palustris L. Sp. PL 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- 

 wdvd. — From the Rocky Mountains eastward across the continent. 



