1 68 ONAGRACEAE. 



237. AMMAWNIA. 



Low and inconspicuous smooth herbs; leaves opposite, narrow; 

 flowers small, 1-several in the axils; calyx bell-shaped, usually 

 4-angled, 4-toothed and with 4 intermediate short tooth-like 

 appendages in the sinuses; petals 4, small, early deciduous, or 

 wanting; stamens 4-8; capsule globular, enclosed in the calyx, 

 mostly 4-celled, bursting irregularly. 



Ammannia coccinea Rottb. Erect or ascending, glabrous, 5-30 cm. high, 

 branched below; leaves oblong-linear, acute or obtuse, auriculate-clasping at 

 the sessile base, entire, 2^ cm. long; flowers 1-5 in the axils, sessile or nearly 

 so; petals broadly spatulate, truncate; style slender, about one-half as long 

 as the capsule. Sandy banks of Snake River at Almota, rare. 



238. ROTALA. 



Low annual mostly glabrous herbs; stems 4-angled; leaves 

 opposite, sessile or sometimes petioled; flowers small, axillary, 

 mostly solitary; calyx 4-lobed; petals 4; stamens 4, short; 

 ovary free from the calyx, globose, 4-celled; capsule globose, 

 enclosed by the membranous calyx, 4-celled, septicidally dehis- 

 cent. 



Rotala ramosior (L.) Koehne. Annual, glabrous, simple or branched below, 

 5-15 cm. high, erect or ascending; leaves entire, oblong or spatulate, obtuse 

 or acute, 1-2 cm. long, narrowed into a short petiole at base, not auricled; 

 flowers mostly solitary in the axils; calyx 2-3 mm. long; petals minute; style 

 very' short. Moist places, especially lake shores and stream banks, rare. 



Family 63. ONAGRACEAE. Evening Primrose Family. 



Herbs with simple alternate or opposite leaves ; stipules none ; 

 flowers perfect, symmetrical, the parts in twos or fours; calyx- 

 tube adherent to the ovary ; petals on the throat of the calyx or 

 rarely wanting; stamens as many as or twice as many as the 

 petals or calyx-lobes, on the calyx-tube; style single, slender; 

 stigma-lobes as many as the cells of the ovary; fruit a capsule 

 or small nut; endosperm none. 



Parts of the flower in twos. 239. Circaea, 169. 



Parts of the flower in fours. 



Fruit indehiscent, nut-like, few-seeded. 240. Gaura, 169. 



Fruit dehiscent, many-seeded. 



Calyx-limb persistent; petals minute or 



wanting. 241. Isnardia, 169. 



Calyx-limb deciduous; petals conspicuous. 

 Seeds silky-hairy; lower leaves mostly 



opposite. 242. Epilobium, 170. 



Seeds not hairy; leaves all alternate. 

 Anthers attached at or near the base, 

 erect. 



