CALLITRICHACEAE. 1 57 



219. EUPHORBIA. Spurge. 



Perennial or annual herbs (in ours); flowers monoecious, in- 

 cluded in a cup-shaped 4-5-lobed involucre resembling a calyx 

 or corolla and usually bearing large thick glands at its sinuses; 

 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. 



Stems prostrate or nearly so; glands of the involucre with 

 petal-like appendages. 

 Seeds with sharp transverse ridges. E. glyptosperma. 



Seeds pitted and wrinkled. E. serpyllifoUa. 



Stems erect; glands of the involucre without petal-like 

 appendages. 

 Leaves filiform, very numerous; seeds smooth. E. cyparissias. 



Leaves not filiform nor very numerous; seeds not smooth. E. dictyosperma. 



Euphorbia glyptosperma Engelm. Annual, glabrous, prostrate or decum- 

 bent; stems much branched from the base, S-30 cm. long; leaves opposite, 

 oblong, obtuse, very oblique at the obtuse or subcordate base, serrulate or 

 sometimes entire, short-petioled, 4-12 cm. long; stipules whitish, fringed; 

 involucres solitary-axillary, somewhat clustered near the tips of the branches, 

 campanulate, 1 mm. long; glands somewhat saucer-shaped, with narrow 

 crenate or lobed appendages; seeds whitish, with sharp transverse ridges, 

 but not pitted. Common in sandy soil, in the warmer valleys. 



Euphorbia serpyllifoUa Pers. Very similar to E. glyptosperma, always 

 prostrate; leaves narrowly obovate, usually cuneate at base; seeds slightly 

 ridged and pitted. In dried-up ponds and stream margins. 



Euphorbia cyparissias L. Perennial, erect, branched above, 30-60 cm. 

 high; leaves numerous, linear, alternate, those at the base of the umbels 

 whorled, sessile, entire, 1-2 cm. long; lower leaves reduced to scales; inflores- 

 cence terminal, a many-rayed umbel; bracts opposite, broadly ovate, sessile, 

 5-8 mm. long, yellowish; involucres campanulate, 2 mm. long; glands crescent- 

 shaped, without appendages; seeds smooth. Sparingly escaped from gardens. 



Euphorbia dictyosperma Fisch. & Mey. Annual, erect, glabrous through- 

 out, 15-30 cm. high, branched above; cauline leaves alternate, obovate or 

 oblanceolate, obtuse, serrate or nearly entire, narrowed into a sessile base, 

 1-3 cm. long; floral leaves opposite, longer than broad, mucronate; involucre 

 about 1 mm. long, the rounded lobes sometimes ciliate; glands transversely 

 elliptical, yellow, about 1 mm. wide; stamens 5-15; styles split only above the 

 middle; capsules subglobose, warty; seeds ovoid, purplish, with low reticulated 

 ridges. Banks of Snake River and at Walla Walla. 



Family 50. CALLITRICHACEAE. Water Starwort Family. 



Aquatic or rarely terrestrial usually tufted herbs; leaves 

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

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



