170 ONAGRACEAE. 



shorter than the blades; flowers perfect, axillary, sessile; calyx 

 turbinate, with 4 segments, persistent; petals 4 and small, or 

 none; stamens 4; filaments short; stigma 4-lobed, often nearly 

 sessile; ovary 4-celled, very short; ovules numerous; capsule 4- 

 angled, septicidal; seeds numerous. 



Isnardia palustris L. Glabrous; stems creeping or sometimes floating, 

 15-30 cm. long; leaves all opposite, ovate or oval, 1-2 cm. long, acute, petioled; 

 flowers sessile, axillary; petals very small and reddish, or none; capsules short- 

 oblong, 4-sided, sessile, not attenuate at base. In ditches and shallow lake 

 borders. Waitsburg, Homer. 



242. EPILOBIUM. WILLOW HERB. 



Mostly perennial herbs; leaves nearly sessile, denticulate or 

 entire, alternate or opposite; flowers axillary or terminal, solitary 

 or clustered; calyx-tube scarcely prolonged beyond the ovary, 

 4-cleft; petals 4, spreading or somewhat erect; stamens 8, the 4 

 alternate ones shorter; fruit a dehiscent capsule; seeds numer- 

 ous, with a tuft of silky hairs at the end. 



Calyx-tube not prolonged beyond the ovary; flowers large. E. angustifolium. 

 Calyx-tube prolonged beyond the ovary; flowers mostly 



small. 

 Annuals; stigmas mostly 4-cleft. 



Stems 8-20 cm. tall, but little branched; herbage 



puberulent. E. minulum. 



Stems 30-90 cm. tall, usually much branched; 



herbage glabrous or glandular. E. paniculatum. 



Perennials; stigmas subentire. 

 Stems tall, 30-90 cm. high. 



Petals 6-10 mm. long; herbage canescent-pu- 



berulent. E. franciscanum. 



Petals 3-5 mm. long; herbage not canescent- 



puberulent. E. adenocaulon. 



Stems low; species mostly alpine or subalpine. 

 Seeds smooth or nearly so. 



Foliage not glaucous. E. hornemanni. 



Foliage glaucous. E. fastigiatum. 



Seeds papillate. 



Plants producing stolons. E. hornemanni. 



Plants not producing stolons. E. ursinum. 



Epilobium angustifolium L. Fireweed. Perennial, erect, about 1 m. high, 

 glabrous or puberulent; leaves numerous, lanceolate, acute, entire or denticu- 

 late, nearly sessile, 8-16 cm. long; lateral veins confluent at the margin; 

 raceme erect, many-flowered, 20-40 cm. long; flowers rose-colored, 2-3 cm. 

 broad; pedicels slender, exceeding the narrow bracts; petals obovate, entire, 

 clawed; stigma 4-lobed; capsules spreading, linear, canescent, 5-10 cm. long. 

 Not uncommon, sometimes a troublesome weed. 



Epilobium minutum Lindl. Annual, simple or branched, puberulent, 

 10-30 cm. high; leaves lanceolate, acute, undulate or denticulate, mostly 

 alternate, 1-2 cm. long, narrowed at base; calyx-tube funnelform; petals 

 pinkish, obcordate, 3-4 mm. long; stigma deeply 4-lobed; capsules short- 

 stalked, curved, ascending or erect, 2-2.5 cm. long. In dry open woods. 



