. 85 



form. This habit seems surprising in the same species with forms that 

 are rigidly erect, but I have failed to find other differences. 

 *463. Polymnia Canadensis radiata xV. Gray. 



Specimens with manifest but not conspicuous rays were collected at 

 Glen Echo, July 1(5, 1897. 

 *48on. Helianthus microcephalus Torr. & Gray. 



Thicket on the slope south of Four Mile Run near Cowdon's, August 

 8, 1899. 

 485. Helianthus decapetalus L. 



Besides the form with thin and ample leaves this has a form with the 

 leaves smaller and firmer: the latter was collected near Gowdon's station. 

 482. Helianthus strumosus L. 



Glen Echo railroad, Connecticut Avenue Bridge, bluffs near Little 

 Falls, M street extended near Eastern Branch. Some of the specimens 

 have considerable pubescence on the under side of the leaves, but it is 

 doubtful whether they are the true variety macrophyllua, 

 482. Helianthus hirsutus Rat. 



There is a well-defined sunflower common in our region for which Brit- 

 ton and Brown's Flora, so far as I can see, makes no provision, but which 

 might very well come under II. hirxiitu* as defined in the Synoptical 

 Flora. According to the latter the stem is "commonly smooth below, 

 rough and hispidulous above", according to the former the stem is 

 "densely hirsute". In our plant, which is of branching habit, the stem 

 is smooth and sometimes glaucous below, or with mere vestiges of rough 

 ness, the branching part rough arid at the extremities somewhat hirsute. 

 The leaves are broadest near the base and long-tapering, scabrous with 

 prickles above and scabrous-pubescent with sparse white horn-shaped 

 hairs beneath. I have little doubt that the description in the Synoptical 

 Flora was intended to cover a plant essentially the same as ours. That 

 of the Illustrated Flora is more true to Rafinesque, but it leaves our 

 plant without a name. 

 490. Coreopsis tinctoria Nutt. 



An occasional escape. South Washington and the Potomac flats 

 dumping ground. 

 4941. Bidens connata Muhl. 



Borders of a pond between Arlington and the river, August 24, 1896; 

 Bennings, September 7, 1899. 

 *494&. Bidens comosa (A. Gray) Wiegand. 



Pond below Arlington, September 14, 1896; Jackson City, September 4, 

 1896; Bladensburg pike, September 16, 1899. 



493. Bidens discoidea (Torr. & Gray.) Britton. (Coreopsis of Ward's 

 Catalogue). 



Bennings, in boggy ground on the flats, September 7, 1899. 

 4930. Bidens sp. 



A single specimen agreeing with some of the material under B. aris- 

 tosa in the National Herbarium was found on the brink of the water at 



