Evening-primrose Family. 57 



LUDWIGIA L. Perennial herbs, with opposite or alternate leaves, and 

 solitary axillary flowers. Calyx-lobes, petals, and stamens 4, or petals want- 

 ing-. Capsule short, many-seeded. 



L. alternifolia L. Seed-box. Stem 2-3 feet high, branched, smoothish 

 slightly wing-angled; leaves lanceolate to linear-lanceolate, alternate, ses- 

 sile; flowers short peduncled; calyx-lobes ovate, acute, reddish; petals yel- 

 low; capsule cubical, wing-angled. Damp soil; June-August; rare; Johnson, 

 and Decatur counties. 



L. polycarpa Short & Peter. Stem 2-4 feet high, glabrous; leaves nar- 

 rowly lanceolate, alternate, sessile, tapering both ways, those of the runners 

 oblong spatulate; flowers small, sessile; capsule 4-sided, longer than the 

 calyx-lobes, ,with 2-linear awl-shaped bractlets from the base. Borders of 

 ponds and in shallow water; July-September; frequent; Fayette, Scott, 

 Muscatine, Johnson, Story, Appanoose, Decatur, Ringgold, and Taylor coun- 

 ties. 



L. palustris (L.) Ell. Marsh or Water Purslane. Stem smooth, creeping or 

 floating; leaves ovate or oval, petioled, opposite; calyx-lobes short; petals 

 small or wanting, reddish in terrestrial forms; capsule oblong, -4-sided, ses- 

 sile. Wet places; July-September; infrequent; Fayette, Muscatine, Johnson, 

 Benton, and Emmet counties. (Isnardht palustris L.) 



EPILOBIUM L. Mostly perennials. Leaves nearly sessile, opposite or 

 scattered. Flowers violet, purple, or white. Calyx-tube scarcely prolonged 

 beyond the ovary; limb 4-5-lobed, deciduous. Petals 4. Stamens 8, with 

 short anthers. Capsule linear, many-seeded. Seeds with a tuft of long hairs 

 at the end, the coma. 



E. angustifolium L. Great Willow-herb. Fire-weed. Stem simple, 4-6 feet 

 high, glabrous or finely pubescent; leaves scattered, mostly entire, narrowly 

 lanceolate, tapering both ways; flowers large, purple, in a long raceme; 

 calyx-limb deeply parted; petals entire; lobes of the stigma long. Rich 

 woods; June-September; frequent; Dubuque, Scott, Johnson, Winnebago, 

 and Shelby counties. (VI Mmaenerion angustifolium (L.) Scop.) 



E. coloratum Muhl. Stem 1-3 feet high, much branched, 4-angled, hoary 

 pubescent; leaves lanceolate, contracted to slender petioles or sessile, 

 acuminate, sharply serrulate or denticulate, lower opposite; flowers small, 

 pale, somewhat nodding, short-peduncled; coma reddish-brown. Low 

 grounds; July-September: common. 



E. adenocaulon Haussk. This species resembles the preceding; leaves 

 lanceolate or ovate-lanceolate, somewhat serrulate or denticulate; inflores- 

 cence and capsules glandular-pubescent; coma white. Wet places; July- 

 September; frequent; Johnson, Story, Hamilton, Floyd, Hancock, Dickinson, 

 and Emmet counties. 



E. lineare Muhl. Stems somewhat branched, mintely hoary-pubescent; 

 leaves numerous, linear or linear-lanceolate, short-petioled; flowers many, 

 small, pale; capsules hoary, coma dingy. Wet places; July-September; in- 

 frequent; Fayette, Scott, Story, Hamilton, and Eramet counties. 



OENOTHERA L. Evening Primkose. Leaves alternate. Calyx-tube pro- 

 longed beyond the ovary, deciduous, limb of 4 reflexed lobes. Petals 4, yel- 

 low in our species. Stamens 8; anthers linear, versatile. 



OE. biennis D. Stem 1-5 feet high, sometimes branched, pubescent or 

 hairy; leaves lanceolate or ovate, tapering both ways, acuminate, remotely 

 toothed, the lowest petioled; flowers in a leafy spike; calyx-tube long; cap- 



