598 ONAGRACEAE (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 mernbranaceous 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. 6NAGRA (Adans.) Ser. Stigma-lobes linear, elongated ; flower-buds up- 

 right; petals yellow; fruit subcylindrical, elongated; seeds in 2 rows in 

 each cell ; caulescent annuals or biennials. ONAGRA Adans. 



it. Pods lance-cylindric or -prismatic, i.e. tapering from a thickish base b. 



b. Petals linear 1. O. orwsiata. 



b. Petals obovate c. 



c. Pods glabrous even when young 2. 0. argillicola. 



c. Pods more or less pubescent at least when young. 



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



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

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

 cence of the stem altogether fine and appressed . . . 8. O. Oakesiana. 

 Sepals appendaged essentially at the tip ; pubescence of the 

 stem usually including long spreading hairs with reddish or 



purplish enlarged bases 4. O. 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 6. 0. biennis. 



a. Pods more slender and of essentially uniform diameter. 



Flowers in a distinct terminal spike 6. 0. rhombipetala. 



Flowers in the axils of foliage leaves. 

 Grayish-pubescent and somewhat silky ; floral leaves mostly entire 



i "or nearly so ; seed smoothish 1.0. humifusa. 



Green, more loosely and sparingly pubescent; floral leaves mostly 



ptnnatifid toward the base ; seed distinctly pitted . . . 8. O. ladniata. 



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 very 

 narrow, linear, 5-12 mm. long, 1-3 mm. wide, light yellow. (O. 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 5-8 mm. wide, subentire or remotely and 

 obscurely few-toothed ; flowers large ; calyx glabrous ; petals bright yellow, 

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

 glabrous, tapering to a slender summit. (Onagra Mackenzie.) Alts, of Va. 

 and W. Va. 



3. 0. Oakesiana Robbins. Finely puberulent, the hairs mainly appressed ; 

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

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

 large, slightly spindle-form, 3.5-4 cm. long, appressed-puberulent. (O. biennti. 

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



4. 0. muricata L. Simple or nearly so, 2-8 din. high, very leafy; stem pu- 

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

 reddish tuberculate bases; leaves lanceolate, ascending, entire or sparingly and 

 very shallowly denticulate, passing 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, subfusiform-cylindric, 2.5-3 cm. long. Sandy or gravelly 

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

 pubescent or somewhat silky throughout, the tuberculate-based hairs few or 

 none. (O. biennis, var. T. & G.; Onagra strigosa Rydb.) From the Great 

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



6. 0. biSnnis L. (COMMON E.) Rather stout, erect, 3-15 dm. high, usually 

 simple, more or less spreading-pubescent to hirsute ; leaves lanceolate to oblong- 

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



