118 ELATINACEAE 



1-2 cm. long, 4-15 mm. wide, 5-nerved at the base; cymes many-flowered, terminal, subulate- 

 bracted; pedicels slender, 2-12 mm. long; flowers 2-4 mm. broad, light orange-yellow; sepals 

 foliaceous, linear-oblanceolate, acutish or obtuse, much shorter than or slightly longer than the 

 petals; stamens 5-12; styles 3; capsule ovoid, pointed, 1 -celled, 2^ mm. long, somewhat longer 

 than the sepals. 



Introduced along ditches and shores; lower Sacramento and lower Sau Joaquin Rivers, California; also 

 Nova Scotia to Manitoba. Kansas, Florida, and Texas. Type locality: Europe. Aug.-Sept. 



Family 95. ELATINACEAE. 



Waterwort Family. 



Low herbs or some tropical species woody, with opposite or verticillate, entire or 

 serrate leaves and small stipules. Flowers small, axillary or fascicled, perfect and 

 regular. Sepals 2-5, imbricated. Petals of the same number as the sepals, hy- 

 pogynous. Stamens of the same number as the petals or twice as many. Ovary 

 2-5-celled; styles of the same number, stigmatic at the apex; ovules many, ana- 

 tropous. Capsule ovoid or globose, septicidal, with the placentae central. Seeds 

 reticulately rugose or ribbed. 



A family of 2 genera and 35 species, of wide geographical distribution. 

 Flowers 2— 4-merous; plants glabrous, growing in or near water. 1. Elatine. 



Flowers 5-merous; plants pubescent, terrestrial. 2. Bergia. 



1. ELATINE L. Sp. PI. 367. 1753. 



Small glabrous herbs, growing in water or creeping on mud, suggesting the chick- 

 weeds in general habit. Flowers minute, mainly solitary in the axils, in submerged plants 

 often remaining closed. Sepals 2-4, membranous, persistent. Petals of the same number. 

 Stamens of the same number or twice as many ; styles 2-4. Capsule globose, membranous, 

 2-4-valved. [Name Greek, meaning fir-like, in reference to the leaves.] 



A genus of 15 species, widely distributed in temperate and tropical regions. Type species, Elatine Hydro- 

 piper L. 



Plowers 2-5-merous, sessile; seeds nearly or quite straight. 



Petals and stamens 3; seeds indistinctly sculptured. 1. E. triandra. 

 Petals and stamens normally 2; seeds distinctly sculptured. 



Leaves obovate; seeds with 9-10 longitudinal lines and 20-30 crossbars. 2. E. americana. 



Leaves oblong or oval; seeds with 6-7 longitudinal lines and 10-12 crossbars. 3. E. hrachysperma. 



Flowers 4-merous, the stamens usually 8, short-pedicelled; seeds strongly curved. 4. E. calif ornica. 



1. Elatine triandra Schk. Long-stemmed Waterwort. Fig. 3239. 



Elatine triandra Schk. Bot. Handb. 1: 345. 1791. 



Plants immersed or terrestrial, tufted or creeping, flaccid, the stems 5-10 cm. long. Leaves 

 oblong or oblanceolate, very thin, 4-8 mm. long ; flowers sessile, minute ; sepals commonly 2 ; 

 petals, stamens and stigmas 3 ; seeds slender, slightly curved, rather faintly sculptured with 

 11-12 longitudinal and 15-20 transverse lines. 



Shallow ponds and pools, Transition Zones; rarely collected, has been found in Washington (Usk), Colo- 

 rado, South Dakota, Nebraska, and Illinois; also in Europe. Type locality: Germany. July-Sept. 



2. Elatine americana (Pursh) Arn. American Waterwort. Fig. 3240. 



Peplis americana Pursh, FI. Amer. Sept. 238. 1814. 

 Elatine americana Arn. Edinb. Journ. Sci. 1:430. 1830. 



Tufted slightly fleshy herb, the stems 2-4 cm. long, growing on mud or often submerged. 

 Leaves obovate, obtuse, 2-6 mm. long ; flowers sessile, 2-merous or rarely 3-merous in the ter- 

 restrial forms ; capsule globose, about 1 mm. in diameter ; seeds nearly 1 mm. long, slightly 

 curved, marked by 9-10 longitudinal lines and 20-30 crossbars. 



Margins of ponds and streams. Transition and Boreal Zones; British Columbia to the mountains of south- 

 ern California and across the continent. Type locality: Pennsylvania. June-Sept. 



3. Elatine brachysperma A. Gray. Short-seeded Waterwort, Fig. 3241. 



Elatine brachysperma A. Gray, Proc. Amer. Acad. 13: 361. 1878. 



Plants tufted, terrestrial or sometimes submerged, the stems 2-5 cm. long. Leaves oblong, 



varying from oval to lanceolate, usually oblong, narrowed at the base, 4-6 mm. long ; flowers 



sessile, minute, 2-merous or rarely 3-merous ; seeds short-oblong, about 0.5 mm. long, distinctly 



sculptured with 6-7 longitudinal lines and 10-12 crossbars. 



Margins of ponds. Upper Sonoran Zone; eastern Washington and Oregon to the Coast Ranges of central 

 and southern California, east to Ohio. Type locality: Illinois. April-May. 



