246 LYTHRACEAE. 



326. 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 dehiscent. 



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 69. 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 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. 327. Circaea, 246. 



Parts of the flower in fours. 



Calyx-limb persistent; petals minute or 



wanting. 328. Isnardia, 247. 



Calyx-limb deciduous; petals conspicuous. 

 Seeds silky-hairy; lower leaves mostly op- 

 posite. 329. Epilobium, 247. 

 Seeds not hairy; leaves all alternate. 



Anthers attached at or near the base, 

 erect. 

 Calyx-lobes reflexed; petals entire. 330. Godetia, 250. 

 Calyx-lobes erect; petals 2-lobed. 331. Boisduvalia, 252. 

 Anthers attached near the middle, 

 versatile. 

 Stamens unequal, the outer ones 



longer. 332. Gayophytum, 252. 



Stamens equal. 



Stigmas deeply 4-cleft, the lobes 



linear. 333. Oenothera, 253. 



Stigmas entire or nearly so. 334. Sphaerostigma, 253. 



327. CIRCAEA. Enchanter's Nightshade. 



Delicate perennial herbs with opposite leaves on slender 

 petioles; flowers white, in terminal or axillary racemes; parts of 

 the flower in twos; calyx-tube prolonged, deciduous; lobes re- 

 flexed; fruit indehiscent, small, bur-like, 1-2-celled, with hooked 

 hairs; cells 1 -seeded. 



