EUPHORBIACEAE. 23I 



glands rounded or often petal-like or crescent-shaped ; staminate 

 flowers numerous, of a single naked stamen, jointed upon a short 

 pedicel which usually has a minute bract at its base; pistillate 

 flowers solitary in the center of the involucre, pedicelled, and 

 soon exserted; calyx none, or rarely present and minute; styles 

 3, 2-cleft; stigmas 6; ovary 3-celled, 3-ovuled. 



Glands of the involucre bearing petal-like appendages; plants 



prostrate or nearly so; seeds pitted and wrinkled. E. serpyllifolia. 



Glands of the involucre not bearing petal-like appendages; 



stems erect ; seeds pitted. E. peplus. 



Euphorbia serpyllifolia L. Annual, glabrous; stems prostrate, much 

 branched from the base, 5-20 cm. long; leaves opposite, narrowly obovate, 

 cuneate at base, serrulate, 4-10 mm. long; stipules fringed; involucres soli- 

 tary-axillary, campanulate, 1 mm. long; glands 4, disc-shaped, each with a 

 lobed appendage; seeds whitish, slightly ridged and pitted. 



In dry soils, often in dried-up ponds. 



Euphorbia peplus L. Annual or biennial; stems erect, 10-30 cm. high; 

 leaves entire, alternate, obovate or the uppermost ovate; flowers umbellate; 

 umbels 3-rayed, then dichotomous; glands of the involucre crescent-shaped, 

 the horns elongated; carpels each with 2 wing-like crests on the back; seeds 

 pale, pitted on the back, grooved on the inner face. 



Sparingly introduced. 



304. PISCARIA. 



Low heavy-scented annual herbs; leaves alternate, entire, 

 3-nerved, petioled, without stipules; flowers monoecious, in 

 axillary cymose fascicles, without an involucre, all apetalous, 

 the pistillate without a calyx; calyx of the staminate flower 

 3-6-parted; stamens 6 or 7, central on the hairy receptacle; style 

 simple, filiform; ovary with 4 or 5 small glands at its base, 1- 

 celled, 1-ovuled; capsule obovate-oblong, 1-celled, 2-valved. 



Piscaria setigera (Hook.) Piper. Turkey Mtdlein. Grayish pubescent 

 with stellate hairs and hispid bristles; stem much branched from near the 

 base, the branches mostly procumbent, 15-60 cm. long; leaves ovate, obtuse, 

 1-5 cm. long, crowded near the tips of the branches; calyx of staminate flower 

 with oblong obtuse lobes; pistillate flowers often in clusters of 2 or 3; ovary 

 and style pubescent; seed shiny, 4 mm. long. 



In dry ground, Columbia River to southern California. The plant was 

 formerly used by the Indians to stupefy fish by throwing quantities of it in 

 the streams. 



Family 54. CALLITRICHACEAE. Water Starwort Family. 



Aquatic or rarely terrestrial usually tufted herbs; leaves op- 

 posite, entire, spatulate or linear, without stipules; flowers 

 minute, perfect or monoecious, axillary; perianth none; bracts 

 two, sac-like, or none; stamen 1 ; pistil 1 ; styles 2, filiform; ovary 

 4-celled; ovule 1 in each cell; fruit nutlike, compressed, 4-lobed, 

 4-celled, more or less winged or keeled; endosperm oily. 



