ONAGRACEAE. 253 



333. OENOTHERA. EVENING PPIMROSE. 



Annual, biennial or perennial herbs with prostrate or erect 

 stems; leaves alternate, entire, toothed or pinnatifid; buds erect 

 or drooping; flowers white, pink or yellow, blooming by night or 

 by day; flowers axillary or in terminal spikes; calyx-tube elong- 

 ated, terete, filiform or enlarged upward; segments narrow, tips 

 free or united in bud, finally reflexed; stamens 8, equal, with 

 filiform filaments and linear anthers; ovary 4-celled, the united 

 styles filiform; stigma 4-cleft; ovules numerous in one, two or 

 more rows, horizontal or ascending; capsule 4-celled, 4-angled, 

 loculicidal; seeds numerous, angled or terete, with or without a 

 tubercle. 



Oenothera biennis L. Biennial, stout, erect, simple or little branched 

 above, 30-100 cm. high, sparsely hirsute throughout; leaves green, oblong- 

 lanceolate to lanceolate, acute or acuminate, repandly denticulate, 5-15 cm. 

 long, all but the basal ones sessile; bracts lanceolate; calyx-tube 2.5-3.5 cm. 

 long; petals obovate, bright yellow, about 2 cm. long; capsule broadest at 

 or near the base. 



Infrequent in open places, especially near the seashore. 0. biennis L. 

 consists of numerous forms or very closely related species at present the sub- 

 ject of much investigation by students 'of heredity. Our form was called 

 0. muricata L. in the Flora of Washington, but is not that plant. 



334. SPHAEROSTIGMA. 



Annual or biennial caulescent herbs; flowers axillary or in 

 spikes; calyx-tube obconical or shortly funnelform; stamens 8, 

 equal in length; anthers attached near the middle, versatile; 

 stigma entire; capsule 4-celled, terete or angled; seeds in one row 

 in each cell. 



Sphaerostigma contortum (Dougl.) Walp. Slender annual, usually branched 

 from the base, 10-15 cm. high, sparsely puberulent or glabrous; leaves nar- 

 rowly linear, entire or denticulate, 2-3 cm. long, sessile; flowers sessile in the 

 axils, somewhat shorter than the leaves; petals reddish-yellow, 2 mm. long, 

 as long as the reflexed calyx-lobes; capsules sessile, linear, somewhat 4-sided, 

 usually twisted or bent at the base, 2-3 cm. long. 



Victoria, British Columbia, Macoun; common east of the Cascade Moun- 

 tains. 



Family 70. HALORAGIDACEAE WATER MILFOIL FAMILY. 



Aquatic or marsh or alpine perennial herbs with inconspicuous 

 symmetrical flowers sessile in the axils of leaves or bracts; calyx- 

 tube adherent to the ovary; calyx-limb very short or none; petals 

 small or none; stamens 1-8; pistil of 1-4 carpels, if more than 

 one, more or less united; styles or sessile stigmas distinct; fruit 

 indehiscent, 1-4-celled with one seed in each cell. 



Stamen 1; ovary 1-celled. 335. HIPPURIS, 254. 



Stamens 2-8; ovary 2-4-celled. 336. MYRIOPHYLLUM, 254. 



