HOFFMANN: FLORA OF BERKSHIRE COUNTY. 347 



P. serpentaria Pursh. Lion's-foot; Gall-of-the-earth. — 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 purple at base. 



c. Heads with green chaff replacing the flowers. 



R. laciniata L. Tall Coxe-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. 



S. VULGARIS L. — Waste ground, Williamstown. 



SERICOCARPUS. White-topped Aster. 



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

 ern part of the valley. 



SOLIDAGO. Golden-rod. 



Kri/ to Solidago. 



a. Hcad.s clu.stcrccl uloiiK the :ixil.-< of the louvt'.-< or in spikes or panicles, not in 



fl;it-topi)cd corymbs. 



b. Bracts of rij^id involucre with abruptly spreading licrliacoous tips; 



heads in dusters or compactly clustered racemes, disjxKsed in a dense 



.somewhat leafy and interrui)led wand-like compound spike; local. 



S. s(Huirrosa. 

 b'. Bracts of the involucre without j^reeii tips and appressed. 



c. Heads clustered ahmR the axils of the leaves, or in wand-like, or 

 pyramidal compact panicles, not in spreadinjt ojien panicles. 



