BICKNELL: FERNS AND FLOWERING PLANTS OF NANTUCKET 105 
which appear to be clearly of hybrid origin, are not less fertile than 
their parent species. And here the possibilities in regard to com- 
pound or even decomposed hybrids opens widely on the view. 
The treatment of the Nantucket blackberries which has 
been adopted in this paper, is allowed to rest frankly on the con- 
siderations here expressed in outline. The sufficient proof that 
many of our distinct appearing blackberries or, indeed, that any 
of them are of hybrid origin is yet to be forthcoming. The evidence 
relied upon in so regarding them is wholly circumstantial. And 
therefore, however well satisfied I may personally be of the hybrid 
origin of many of the plants here described, it must be understood 
that a mark of interrogation should apply to every one of them, 
first, as to its actual hybrid character and, second, as to whether 
if a hybrid the factors in its parentage have been correctly 
suggested. 
The study of the blackberries of Nantucket, far from being 
completed, must be regarded as only just begun. With each 
succeeding visit to the island I have more acutely realized that a 
series of fleeting visits, wherein the entire flora was under observa- 
tion, was wholly inadequate for an effective study of so exacting 
and recondite a problem as that which the group presents. 
A series of specimens representing all of the hybrid blackberries 
herein described has been deposited in the herbarium of the New 
York Botanical Garden. 
Rusus stricosus Michx. 
Abundant on Coskaty, and occasional in thickets on the 
eastern side of the island: Saul’s hills; Rattlesnake Bank, Quaise, 
Polpis, Pocomo, and Squam. In full flower as late as June 20, 
1910. 
*RUBUS OCCIDENTALIS L. 
Thickets at Shawaukemmo Spring, where it fruits abundantly 
and appears to be native; occasional by street sides and fence 
rows in the town and suburbs, appearing as if introduced. 
RuBusS TRIFLORUS Richards. 
Reported as a Nantucket plant in Mrs. Owen’s catalogue; on 
the authority of Mr. Dame, from ‘‘bog near Sancoty”’ [Sankaty]. 
