282 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM. 



20. Aster paniculatus Lam. 



Ijow ground; chiefly along the Potomac, but also northeastward. Aug. -Oct. 

 Eastern N. Amer. (.4. simplex of Ward's Flora.) 



21. Aster tradescanti L. 



Rock Creek region and perhaps elsewhere. Sept.-Oct. Eastern U. S., south to 

 Va. 

 Our form may not be essentially different from A. laterijlorus. 



22. Aster ericoides L. 



Dry or moist fields and hillsides; common. Sept.-Oct. Eastern N. Amer. 



13. DOELLINGERIA Nees. 



Achenes pubescent; involucres about 4 mm. long; leaves lanceolate or ovate. 



1. D. umbellata. 

 Achenes glabrous; involucres 6-7 mm. long; lower leaves olten obovate. .2. D. infirma. 



1. Doellingeria umbellata (Mill.) Nees. 



Dry or moist fields or woods; common. July-Oct. Eastern N. Amer. (Aster 

 umbellatus Mill.; Diplopappus umbellutus Hook.) 



2. Doellingeria infirma (Michx.) Greene. 



Dry or moist fields and woods; frequent. July-Oct. Eastern IT. S. (Aster injirmus 

 Michx.; Diplopappus cornifolius Less.) 



14. IONACTIS Greene. 



1. Ionactis linariifolius (L.) Greene. 



Dry or rocky woods; common. Sept.-Oct. Eastern U. S. (Aster linariifolius L.; 

 Diplopappus linariifolius Hook.) 



A handsome plant, resembling an Aster, with showy violet rays; leaves linear and 

 rather stiff. 



15. ERIGERON L. 



Plants perennial; stem leaves sessile and usually clasping; rays commonly bluish 

 purple or pink. 

 Plants producing slender Btolons; heads 12-18 mm. broad; rays about 50; leaveB 



densely long-hairy 1. E. pulchellus. 



Plants without stolons; heads about 10 mm. broad; rays very numerous, 100 or more; 



leaves nearly glabrous 2. E. philadelphicus. 



Plants annual or biennial; stem leaves, at least the lower ones, petioled; rays very 

 numerous, usually white, sometimes pinkish. 

 Pubescence of the stemB composed of few long soft spreading hairs; leaves coarsely 



and sharply toothed, the lower ones ovate or oval 3. E. annuus. 



Pubescence of the stems composed of short appressed hairs; leaves entire or very 

 obscurely and remotely toothed, the lower ones oblanceolate. ..4. E. ramosus. 



In the National Herbarium there is a specimen of Erigeron vernus (L.) Torr. & Gray 

 said to have been collected in the vicinity of Washington by Gerald McCarthy; prob. 

 ably it is wrongly labeled. 



1. Erigeron pulchellus Michx. Robin's plantain. 

 Woods and meadows; common. Apr.-May. Eastern U. S. (E. bcllidifolius Muhl.)- 

 A colony of flowering plants is shown in plate 41B. 



2. Erigeron philadelphicus L. Fleabane. 

 Fields and wet meadows along the Potomac; frequent. May-June. Nearly 



throughout the U. S. and Can. 



3. Erigeron annuus (L.) Pers. White-top. 

 Fields; very abundant. June-Oct. Eastern N. Amer. 



