3(2). Seeds 20 or more in each cell; pits 25 to 35 in each row 3. E. chilensis. 



3. Seeds 15 or fewer in each cell; pits 16 to 25 in each row 4. E. triandra. 



1. Elatine californica Gray. Fig. 532. 



Matted prostrate plant of muddy shores or erect aquatic; leaves short -petioled to 

 subsessile, obovate to oblanceolate, 4-12 mm. long; flowers on short pedicels, the 

 pedicel elongating in fruit to become 1 to 2 times as long as the fruit; sepals 4, 

 equal or subequal to one another in size, oblong, united at base and growing with 

 the fruit: petals 4, obovate; stamens 8; capsule with 4 carpels; seeds J- or U-shaped, 

 rounded at one end and truncate at the other with a subapiculate base. 



In ponds, vernal pools, in wet mud on margins of lakes, streams and ditches, in 

 Ariz. (Coconino Co.). July-Sept.; Mont, to Wash., s. to n. Ariz, and Calif. 



2. Elatine brachysperma Gray. Fig. 533. 



Plant forming tiny low spreading mats to 5 cm. across, the branches somewhat 

 ascending; leaves to 6 mm. long and 2 mm. wide; flowers sessile, 3-merous; sepals 

 2 or with a third greatly reduced; petals 3, pinkish; capsule depressed, 3-celled; 

 seeds shortly oblong-ellipsoid, with 9 to 15 pits in each triangular row, the pits 

 separated by acute cross-ribs. E. triandra var. brachysperma (Gray) Fassett. 



Rare on mud about vernal pools, ponds and in ditches, or in shallow water in 

 cen. Tex., Okla. (Comanche Co.) and Ariz. (Apache, Coconino and Gila cos.), 

 Mar.-Oct.; O. and 111. w. to Ore., s. to Okla., Tex., Ariz, and Calif. 



3. Elatine chilensis Gay. Fig. 534. 



Plants to about 10 cm. long, aquatic or when on wet mud creeping and rooting 

 at nodes; leaves obovate to broadly spatulate, rounded at summit, 3-4 mm. long, 

 1-3 mm. wide, narrowed at base to a petiole, with entire triangular attenuate 

 hyaline stipules; flowers solitary in leaf axils, sessile; sepals 2, oblong, sometimes 

 with a third much reduced one present; petals white to pink, orbicular; stamens 3, 

 alternate with the carpels; seeds 20 or more in each cell, borne at the base of the 

 placental axis, erect, cylindric, slightly curved, with 25 to 35 short broad pits in 

 each row. with the transverse ridges more conspicuous than the longitudinal ones 

 (the seed therefore appearing as though transversely rugose). 



In mud on shores of lakes and ponds, Ariz. (Coconino Co.), May-Aug.; also 

 Calif, and S.A. 



4. Elatine triandra Schkuhr. 



Matted creeping plant; leaves mostly truncate or emarginate, to 7 mm. or more 

 long and 3 mm. wide; flowers sessile, 3-merous; seeds 15 or less in each cell, 

 borne along entire length of thickened central axis, horizontally divergent, slender- 

 cylindric and curved, with meandering obscure longitudinal ridges and somewhat 

 angular pits in each row, the larger seeds with 15 to 25 pits in each row. (?) E. 

 americana (Pursh) Am. 



In mud and shallow water in cen. Tex., Okla. (Comanche Co.), N. M. (Sandoval 

 Co.) and Ariz. (Apache and Coconino cos.), Mar.-Oct.; from Wise, to Alta. and 

 Wash., s. to Tex. and n. Mex.; also Euras. 



2. Bergia L. 



A small essentially tropical or subtropical genus of about 20 species. 

 1. Bergia texana (Hook.) Walp. Fig. 535. 



Diffuse or ascending plant that is branched from the base, to 4 dm. tall, more or 

 less glandular-puberulent throughout; flowers shortly pedicelled, 1 to 3 in the axils 

 of the leaves; leaves elliptic-oblong to oblong-oblanceolate, tapering at base, serru- 

 late, to 3 cm. long; stipules lanceolate, deeply serrate; sepals 5, to 3.5 mm. long, 



1145 



