840 EPILOBIACEAE 



cm. broad : capsules narrowly oblong-conic, erect, pubescent, 18-25 mm. long, nearly terete. 



[ Oenothera biennis L. ] 



In dry or stony soil, Labrador to Florida west to the Mississippi Valley. Summer and fall.— A 

 variety, O. biennis grandifldra{ Ait.) hind!., is larger and stouter, has larger, thicker and broader leaf- 

 blades and a corolla 5-8 cm. broad ; it is more common in the southern part of the range. 



2. Onagra Jamfesii (T. & G. ) Small. Stems stout, canescently strigillose, decumbent, 

 1-4 m. long, more or less branched : leaf-blades narrowly oblong or lanceolate, 5-20 cm. long, 

 often curved, acute, repandly denticulate, the lower ones narrowed into short petiole-like 

 bases, the upper sessile or nearly so : hypanthium stout, 5-11 cm. long : sepals nearly linear, 

 about half as long as the hypanthium : corolla showy, yellow, turning to rose : capsules 

 tapering upward, 35-40 mm. long. \_Oenothera Jamesii T. & G.] 



In dry soil, southern Utah to Texas and Arizona. Summer. 



8. OENOTHERA L. 



Caulescent annual biennial or perennial herbs, with depressed or erect stems. Leaves 

 alternate : blades sinuate or pinnatifid. Flowers axillary, or sometimes in terminal spikes, 

 nocturnal. Buds erect. Hypanthium filiform or slender. Sepals deciduous. Corolla yel- 

 low. Ovary 4-celled, elongated. Ovules in 2 rows, ascending. Capsule usually narrowly 

 cylindric, sometimes slightly tapering, spreading or ascending. Seeds terete, each crowned 

 with a tubercle. Evening primrose. 



Flowers axillary. 



Stems clothed with dense appressed Or ascending hairs. 



Corolla 2-3 cm. broad : species native along the Atlantic Coast. 1. 0. humifusa. 



Corolla 7-9 cm. broad : species native along the western Gulf Coast, occasion- 

 ally naturalized on the Atlantic Coast. 2. O. Drummondii. 

 Stems glabrous or rarely with spreading hairs. 3. O. laeiniata. 

 Flowers in a terminal bracted spike. 



Spike lax : bracts ovate : hypanthium villous. 4. 0. heterophylla. 



Spike dense : bracts narrow : hypanthium silky-strigose. 5. O. rhombipetala. 



1. Oenothera humifusa Nutt. Stems branched at the base, the branches spreading, 

 decumbent or ascending, 2-5 dm. long, silky canascent : leaves various, the basal with ob- 

 long-spatulate pinnatifid blades, the cauline with oblanceolate to lanceolate acute, undulate 

 repand or toothed blades, 2-3.5 cm. long : flowers axillary : hypanthium 2-3 cm. long : sepals 

 about 2 as long as the hypanthium : corolla 2-3 cm. broad : capsules narrowly cylindric, 2-3 

 cm. long, somewhat curved upward : seeds 1.5-2 mm. long, striate. 



In drifting sand along the coast, New Jersey to Florida. Spring to fall. 



2. Oenothera Drummondii Hook. Stems branched at the base, the branches de- 

 cumbent, 2-7 cm. long, pubescent with appressed stiff-silky hairs : leaves various ; blades 

 spatulate to lanceolate, or sometimes ovate or obovate towards the ends of the branches, 

 1-4 cm. long, entire or distantly toothed : flowers axillary : hypanthium stout, 2-4 cm. 

 long : sepals nearly linear, more than f as long as the hypanthium : corolla 7-9 cm. broad : 

 capsules cylindric, 2.5-4 cm. long, spreading, curved upward : seeds nearly 1.5 mm. 

 long, pitted. 



On the coast of Texas. Spring to fall. 



3. Oenothera laeiniata Hill. Stems decumbent or ascending, sometimes branched, 

 1-5 dm. tall, glabrous or sparingly hirsute : leaf-blades oval, lanceolate, oblong, or oblan- 

 ceolate to spatulate at the base of the plant, 2.5-5 cm. long, acute or obtusish at the apex, 

 sinuate-dentate or often pinnatifid : flowers axillary : hypanthium 3-4 cm. long : sepals re- 

 flexed : corolla 12-36 mm. broad : capsules linear-cylindric, 2.5-3.5 cm. long, more or less 

 pubescent: seeds 1.2-1.5 mm. long, strongly pitted. \_Oenothera sinuata L.] 



In dry sandy soil, southern Vermont to New Jersey, Nebraska. Florida, Texas and Mexico, extend- 

 ing into South America. Spring and summer. — 0. laeiniata grdndis Britton, with more prominently 

 toothed leaf-blades and corollas 5-7 cm. wide, ranges from Missouri to Kansas and Texas, and 0. 

 laeiniata Mexicdna (Spach.) Small, with shaggy hirsute stems, leaves and capsules, occurs in Texas and 

 northern Mexico. 



4. Oenothera heterophylla Spach. Stems relatively slender, erect, 4-9 dm. tall, 

 rather sparingly appressed-pubescent : leaf-blades narrowly oblong to lanceolate, sometimes 

 narrowly lanceolate or spatulate on the lower part of the stem, 1-6 cm. long, acute, undu- 

 late or remotely and shallowly toothed, sessile and slightly clasping on the upper part of 

 the stem : corolla 2-4 cm. broad : sepals sparingly and loosely glandular-pubescent : petals 

 obovoid, 1-2 cm. long : capsules columnar, but slightly tapering to the apex, curved, 

 1.5-2 cm. long, loosely pubescent : seeds fully 1 mm. long. 



In sandy soil, sometimes in woods, Florida to Texas. Spring and summer. 



5. Oenothera rhombip6tala Nutt. Stems relatively stout, erect, 6-12 dm. high, 

 finely and densely appressed-pubescent : leaf-blades lanceolate to linear-lanceolate or 



