HOFFMANN: FLORA OF BERKSHIRE COUNTY. 347 



P. serpentaria Pursh. Lion's-foot; Gall-of-the-eahth. — Dry 

 thicket, Sheffield. 



P. trifoliata (Cass.) Fernald. Gall-of-the-earth. — Woods; 

 common. Summit of Greylock, 3400 feet. 



RUDBECKIA. Cone-flower. 



R. HiRTA L. Black-eyed Susan; Yellow Daisy. — Fields; 

 common. Not mentioned by Dewey. Introduced from the West 

 after 1850. 



The following forms have been noted : — 



a. Rays greenish or streaked with green. 



b. Rays pm-ple at base. 



c. Heads with green chaff replacing the flowers. 



R. laciniata L. Tall Cone-flower. — Borders of streams, moist 

 banks and upland meadows; frequent. The double form, cultivated 

 under the name " Golden Glow " occasional as an escape. 



SENECIO. Groundsel; Ragwort. 



S. aureus L. Golden Ragwort. — Low woods, wet meadows and 

 swamps; common. 



S. obovatus Muhl. — Rocky woods, moist banks and ledges; com- 

 mon in calcareous soil, and frequent elsewhere. 



5. vulgaeis L. — Waste ground, Williamstown. 



SERICOCARPUS. WmTE-TOPPED Aster. 



S. asteroides (L.) BSP. — Dry open woods; frequent in the south- 

 ern part of the valley. 



SOLIDAGO. Golden-rod. 



Key to Solidago. 



a. Heads clustered along the axils of the leaves or in spikes or panicles, not in 

 flat-topped corymbs. 



6. Bracts of rigid involucre with abruptly spreading herbaceous tips; 



heads in clusters or compactly clustered racemes, disposed in a dense 

 somewhat leafy and interrupted wand-like compound spike; local. 



iS. squarrosa. 

 b'. Bracts of the involucre without green tips and appressed. 



c. Heads clustered along the axils of the leaves, or in wand-Uke, or 

 pyramidal compact panicles, not in spreading open panicles. 



