SPRING FLORA 



1. O. polyacantha Haw. (O. missouriensis DC.) Joints 

 strongly compressed (except in young seedlings) ; broadly ob- 

 ovate and tuberculate, 2-4 inches long; leaves very small, 

 their axils armed with a tuft of slender bristles. Flowers 

 pale yellow. Fruit dry, very spiny. In dry soil on hillsides. 

 May-June. 



2. O. fragilis (Nutt.) Haw. Joints compressed or sometimes 

 terete; 1-1% in. long, ovoid or subglobose. Leaves very small, 

 reddish. Areolae with few bristles; central spines 1-4. Flowers 

 yellow, smaller than those of No. 1. Fruit dry, with areolae 

 of spines and a few short bristles. In dry soil. Maj^-June. 



ORDER MYRTAL.ES. 



ONA GRACED. Evening Primrose Family. 



Herbs with simple, usually exstipulate leaves. Inflor- 

 escence axillary or terminal; solitary, spicate or race- 

 mose. Flowers complete; regular; symmetrical. Sepals 

 epigynous ; usually 4. -Petals 2-6, usually 4; perigynous. 

 Stamens 2-12, as many or twice as many as petals; 

 perigynous. Ovary usually 4- celled, and then with 

 many ovules on axile placentae; conspicuously "in- 

 ferior." Stigma 2-4-lobed or capitate. Fruit a capsule 

 or nutlet. 



Ovary 4-celled. many-seeded; fruit a capsule. 



Lower leaves opposite; seeds comose at apex.. 1. Epilobium 

 All the leaves alternate (or basal); seeds not comose. 

 Petals yellow, white or rose; anthers ver- 

 satile 2. Ocnothera 



Petals purple or red-violet; anthers erect. . . 3. Clarkia 

 Ovary 1-celled, 1-4-seeded; fruit nut-like, indehiscent. . 4. Gaura 



1. EPILOBIUM. Willow Herb. 



Leaves nearly sessile, with entire or serrate margins. Calyx 

 4-parted. Petals 4. Stamens 8, the alternate ones the longer. 

 Capsule loculicidal, 4-angled; the seeds with a tuft of long 

 hairs at the apex. 



Annual; leaves entire or nearly so 1. E. paiiiculatum 



Perennial; leaves serrulate or denticulate.... 2. E. adeuocaulon 



1. E. paniculatum Nutt. Slender-stemmed, erect and often 

 diffusely-branched; glabrous or somewhat glandular-pubescent 

 above; 6-36 inches high. Leaves linear or lanceolate; obscure- 

 ly serrulate. Flowers few, small, terminal. Petals white or 

 rose-color, notched at apex. On plains and in canyons. June- 

 September. Varying much in size and branching according to 

 water-supply of its habitat. 



