1921] Reports on the Flora of the Boston District,— XXXIV 113 



dence of iheir ever becoming detached from the parent plant to act 

 in any reproductive function. 



The fruit of the form varies; many plants have normal full-grown 

 carpels, while in others they are small, half-developed, and resemble 

 those of 8. Carsonii Durand. 



It might also be well to add that the stem is much more fragile 

 than in the common forms, and it is so brittle especially at the base 

 that it was difficult, even in the soft mud of the tidal flats, to pull 

 up the plants by the roots without breaking them at that point. 



At a few places on the estuary were clumps of 8. suave which grew 

 so that the individuals were partially supported by the dense vege- 

 tation, and these tended less to take on the form with fascicled leaves, 

 and showed a gradual transition into the typical form of the species. 

 But whether or not the development of this form has any direct 

 relation with the degree of recumbence cannot be stated with any 

 degree of certainty. 



Siwn Carsonii Durand is apparently merely a weak aquatic state 

 of S. suave, and should be considered as a form, likely to occur any- 

 where throughout the range of the species as a response to sub- 

 mergence. 



Sium suave Walt, forma Carsonii (Durand), comb. nov. S. 

 Carsonii Durand in Gray, Man. ed. 5, 196 (1867). S. cicutacfolium 

 Schrank \ar. Carsonii (Durand) Eames, Rhodora, xviii. 239 (1916). 



Harvard University. 



REPORTS ON THE FLORA OF THE BOSTON 

 DISTRICT— XXXIV. 



[There is an insignificant specimen of Mentzelia in the Club Herb- 

 arium collected in Boston by C. E. Perkins in 1882. There are also 

 records of Opuntia vulgaris Mill, by John Robinson, Fl. Essex Co., 

 55, 1880, but apparently the plants were introduced and not per- 

 sistent.] 



THYMELEACEAE. 



DAPHNE. 



D. Mezereum L. Spontaneous or persistent at Ipswich, Salem, 

 and Medford. 



