FLOEA OF THE DISTRICT OF COLUMBIA. 213 



Calyx tube prolonged beyond the ovary. • 



Seeds furnished with a tuft of silky hairs; flowers pink; leaves opposite, or 



alternate above 7. EPILOBrUM. 



Seeds naked; flowers yellow; leaves alternate. 

 Stamens equal in length; fruit long, cylindric. 

 Plants large (30-150 cm. high), rather stout; leaves minutely toothed; seeds 



horizontal, angled 8. OENOTHERA. 



Plants small (10-70 cm. high), slender; leaves lobed; seeds ascending, not 



angled 9. RAIMANNIA. 



Stamens unequal in length, the alternate longer; fruit short, obovoid. Leaves 

 linear to oblong, entire or with very small teeth 10. E^TEIFFIA. 



1. CIRCAEA L. Enchanter's nightshade. 



1. Circaea latifolia Hill. 

 Woods; common. June-Aug. Eastern U. S. (C Zrtfeiiana of American authors.) 



2. GAURA L. 

 1. Gaura biennis L. 

 Dry soil; frequent. Aug.-Oct. Eastern N. Amer. 



3. CHAMAENERION Adans. 



1. Chamaenerion angustifolium (L.) Scop. Purple fireweed. 



Clearings and newly burned lands; infrequent. Aug. Widely distributed in N. 

 Amer.; also in Eiir. and Asia. {Epilobium angustifolium L.) 



4. JUSSIAEA L. 



1. Jussiaea decurrens (Walt.) DC. 

 Wet places along Hunting Creek. Aug.-Sept. Southeastern U. S., north to Md. 



6, ISNARDIA L. i 



1. Isnardia palustris L. Water purslane. 



Ditches and swamps along the Potomac and its larger tributaries; frequent. July- 

 Aug. Widely distributed in N. Amer. and in the Old World. {Ludwigia palustris 

 Ell.) 



A succulent plant with ovate leaves tapering to a slender petiole. It forms a 

 characteristic reddish mat in our small streams and swamps. 



6. LUDWIGIA L, 



Plants hirsute; capsules bristly-pubescent; leaves oblong, or the upper lanceolate, 

 blunt at both ends, sessile 1. L. Mrtella. 



Plants glabrous; capsules glabrous; leaves lanceolate or linear-lanceolate, acute or 

 pointed at both ends, short-petioled 2. L. altemifolia. 



1, Ludwigia hirtella Raf. 



Holmead Swamp; not collected recently. July-Aug. N. J. to Tex. 



2. Ludwigia altemifolia L. Seed-box. 

 Low woods and swamps; common. June-Aug. Eastern U. S. 



7. EPILOBITTM L. Willow-hehb. 



1, Epilobium coloratum Muhl, 

 Low ground; frequent. Aug. Eastern U. S. 



