598 ONAGKACEAE (EVENING PRIMROSE FAMILY^ 



4. OENOTHERA L. Evening Primrose 



Calyx-tube prolonged beyond the ovary, deciduous ; the lobes 4, reflexed. 

 Petals 4. Stamens 8 ; anthers mostly linear and versatile. Capsule 4-valved, 

 many-seeded. Seeds naked or with an obscure membranaceous crest. — Leaves 

 alternate or rarely all basal. Flowers yellow, white, or rose-color. (An old 

 name of unknown origin, for a species of Epilobium.) 



§ 1. ONAGRA (Adans.) Ser. Stigma-lobes linear, elongated ; floiver-hnds up- 

 right; petals yellow; fruit suhcylindricaL elongated; seeds in 2 rows in 

 each cell ; caulescent annuals or biennials. Onagra Adans. 



</. Pods lance-cylindric or -prismatic, i.e. tapering from a tbickisli base b. 



b. Petals linear \. O. cruciata. 



b. Petals obiovate c. 



c. Pods glabrous even wben young . . ' "i. O. argillicola. 



c. Pods more or less pubescent at least when j'oung. 



Bracts decidedly leaf-like. i.e. at least the lower tlowers in the axils 

 of foliage leaves, even the tipper bracts exceeding the pods. 

 Sepals appendaged on the back somewhat below the tip ; pubes- 

 cence of the stem altogether fine and appressed . . .8. 0, Oakesiana. 

 Sepals appendaged essentially at the tip ; pubescence of the 

 stem usually including long si)reading hairs with reddish or 



purplish enlarged bases 4. 0. muricata. 



Bracts reduced and somewhat deciduous, the flowers and espe- 

 cially the pods in elongated exposed spikes, the upper bracts 



usually shorter than the pods 5. 0. biennis. 



a. Pods more slender and of essentially uniform diameter. 



Flowers in a distinct terminal spike &. 0. rhombipetala. 



Flowers in the axils of foliage leaves. 

 Grayish-pubescent and somewhat silky ; floral leaves mostly entire 



or nearly so ; seed smoothish 1.0. humifiisa. 



Green, more loosely and sparingly pubescent; floral leaves mostly 



pinnatifid toward the base ; seed distinctly pitted . . . S. 0. laciniata. 



1. 0. cruciata Nutt. Simple or sparingly branched, 3-8 dm. high ; stem com- 

 monly reddish, smooth or somewhat strigose ; stem-leaves lanceolate, remotely 

 and shallowly dentate ; sepals appendaged somewhat below the tip ; petals veiy 

 narroin., linear, 5-12 mm. long, 1-3 mm. wide, light yellow. (0. biennis, var. 

 T. & G.; Onagra cruciata Small.) — Sandy or gravelly soil, centr. Me. to w. 

 Mass. and n. N. Y. 



2. 0. argillicola Mackenzie. Glabrous, 5-15 dm. high ; stem stoutish, very 

 leafy ; leaves linear-lanceolate, only jVS mm. wide, subentire or remotely and 

 ob.scurely few-toothed ; flowers large ; calyx glabrous ; petals bright yellow, 

 broadly obovate, 3-4 cm. long ; capsules crowded, mostly curved, 2-3 cm. long, 

 glabr(jus, tapering to a slender summit. (Onagra Mackenzie.) — Mts. of Va. 

 and \V. Va. 



3. 0. Oakesiana Robbins. Finely puberulent, the hairs m2iin\y appressed ; 

 stem-leaves lanceolate, shallowly denticulate, 8-15 mm, broad ; sejyals append- 

 aged considerably below the tip; petals obovate, 1.5-2 cm. long; pod.^^ rather 

 large, slightly .spindle-form, 3.5-4 cm. long, appressed-puberulent. (0. biennis, 

 var. Gray ; Onagra Britton, in part.) — Sandy fields, etc., e. Mass. to Ct. 



4. 0. muricata L. Simple or nearly so, 2-8 dm. high, vei'y leafy; stem pu- 

 berulent and usually beset at least above with lougav spreading hairs on enlarged 

 reddish tuberculate bases; leaves lanceolate, ascending, entire or si)ariiigly and 

 very shallowly denticulate, pa.ssing without marked transition into the foliaceous 

 bracts; flowers axillary, the lower much exceeded by the bracts; sepals not 

 prominently appendaged ; petals obovate, light yellow, 1.2-2 cm. long; capsule 

 more or less hirsute, subfu.siform-cylindric, 2.5-3 cm, long. — Sandy or gravelly 

 shores, Nfd. and e. Que. to N. Y. Var. oanesckns (T. & G.) Robinson. Hoary- 

 pubesct'ut or somewhat silky throughout, the tuberculate-based hairs few or 

 none. (0. biennis, var. T. & G.; Onagra strigosa Rydb.) — From the Grt^at 

 Lakes to Mo., Col., and north westw. 



5. 0. biennis L. (Common E.) Rather stout, erect, 3-15 dm. high, usually 

 simple, n)ore or less spreading-pubcscent to hirsute ; leaves lanceolate to oblong- 

 or rarely ovate-lanceolate, repandly denticulate, acute or acuminate ; bracts 



