214 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM. 



8. OENOTHERA L. Evening primrose. 

 1. Oenothera biennis L. 



Open places; common. July-Sept. Eastern N. Amer 

 J^TT? V ?. rlable *P ecie8 > in re <" ent y^rs the subject of extensive investiga- 

 te s » thin tv k J T ieS i 8 COnddered to C ° nSi8t ° f ™™™ s Elementary 

 species three of which have been described by Bartlett' from our region: steno- 

 meres, 0. bremcapiula, and 0. ruderalis. 0, stenomeres is a form with linear petals 



9. RAIMANNIA Rose. 

 1. Eaimannia laciniata (Hill) Rose. 



Dry open places northeastward; infrequent. May-July. Eastern U. S. (Oeno- 

 thera sinuata L.; 0, laciniata Hill.) v 



10. ZNEIFFIA Spach. Stjndrops. 



^^oTthrnll ( r!! ly l Cm ; T^ ° r l6HS) - Fl0WeM m ° Stl y b0rne 0n the "PPer third 

 of the plant and separated from the main leafy portion by an elongate internode. 



Flowers large (1.5-2.5 cm. broad or more). lm K ' P umUa - 



Pedicels elongate, longer than the capsule.... a B: t^mt^At. n * 



Pedicels shorter than the capsule. ' Ion ^ edlcellate - 



Capsule markedly club-shaped, tapering from the summit to the base. 



Capsule oblong or nearly so, tapering slightly at the base IKtSbZ^ 



1. Kneiffla pumila (L.) Spach. 



P IiL d L) nd ° Pen PlaCe8: infreqUGnt May_JUne - Ea8ternN - A ^r. (Oenothera 



2. Kneiffla longipedicellata Small. 



Moist soil, chiefly eastward; frequent. May-July. Eastern U S (Oenothera 

 longipedicellata Robinson.) (Venothera 



3. Kneiffla linearis (Michx.) Spach 



4. Kneiffla frnticosa (L.) Raim. 



Dry soil; common. May-June. Eastern U. S. (Oenothera frnticosa L.) 



Trapa natans L of the family Trapaceae, native of Eur., was formerly established 

 in fish ponds in Potomac Park but is now extinct. estaoiisned 



113. HAIOEAGIDACEAE. Water milfoil Family. 



Leaves all dissected into hairlike lobes 2 myeiopttyt t mur 



dtrcti^ ^ UPPer ° nea ' 8imple ' Shall °^ tootnedVtie^o^S 

 2. PROSERPINACA. 



1. MYRIOPHYLLTTM L. Water milfoil. 

 1. Myriophyilum spicatum L. 

 Hunting Creek. Widely distributed in N. Amer., Eur., and Asia 

 Myriophyilum proserpinacoides Gill., parrofs-feather, a native of Chile is cultivated 



attntLm * "^ "^ " makeB a 8trikin 8 dis ^ »* ^tracts much 



1 Cybele Columb. 1: 37-36. 1914. 



