Flora of the Palouse Region 1 1 1 



and subtended by an involucre which resembles a calyx: parts of 

 flowers various, often different in staminate and pistillate flowers: 

 calyx none or minute: petals often wanting: stamens i-many, free 

 or united: pistil usually 3-celled: fruit a 3-lobed capsule: endos- 

 perm copious. 



179. EUPHORBIA. 



Perennial or annual herbs: flowers monoecious, included 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 usu- 

 ally has a minute bract at its base: pistillate flowers solitary in the 

 center of the involucre, pedicelled, and soon exserted: calyx 

 minute or none: styles 3, 2-cleft; ovary 3-celled, 3-ovuled. 



Glands of the involucre with petal-like appendages: leaves opposite. 



Seeds with prominent regular transverse ridges. E. Glyptosperma. 



Seeds faintly ridged and pitted. E. SERPyllifoeia. 



Glands of the involucre naked: leaves alternate. 



Leaves serrulate. E. arkansaxa. 



Leaves entire. E. cvparissias. 



E. glyptosperma Engelm. Annual, glabrous, prostrate or decumbent: 

 stems much branched from the base, 5-30 cm. long: leaves opposite, oblong, 

 obtuse, very oblique at the obtuse orsubcordate base, serrulate, short-petioled, 

 4-12 cm. long; stipules whitish, fringed: involucres solitary-axillary, some- 

 what 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. Banks of Snake 

 River. 



E. serpyllifolia Pers. Very similar to the above, always prostrate: leaves 

 narrowly obovate, usually cuneate at base: seeds slightly ridged and pitted. 

 In dried up ponds and stream margins. 



E. arkansana var. missouriensis Norton. Annual, erect, glabrous 

 throughout, 15-30 cm. high, branched above: cauline leaves alternate, obo- 

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

 base, 1-3 cm. long: floral leaves opposite, longer than broad, mucronate: in- 

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

 transversely elliptical, yellow, about I mm. wide: stamens 5-15: styles split 

 only above the middle: capsules subglobose, warty; seeds ovoid, purplish, 

 with low reticulated ridges. Ranks of Snake River, rare. 



E. 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: inflorescence 

 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 gar- 

 dens. 



