BICKNELL: FERNS AND FLOWERING PLANTS OF NANTUCKET 71 
* SEDUM PURPUREUM Tausch. 
Bank near the Orange Street railroad crossing ; dry field over 
a mile west of the town. First observed June, 1908. 
SEDUM ACRE L. 
At two localities in dry fields near Millbrook Swamp; bank 
on Grove Lane; Poor House grounds and roadsides near by. 
GROSSULARIACEAE 
GROSSULARIA HIRTELLA (Michx.) Spach. 
Thickets or open ground either in dry or moist soils, some- 
times in open boggy places. In full bloom May 31, 1909, a few 
flowers as late as June 20; some fruit nearly full size June 7. 
Not a few of the plants of Nantucket differ from the ordinary 
form of their species found on the mainland. The variations from 
their common types displayed by such species may be either 
slight and inconstant or well emphasized and firmly established. 
And there may be discerned a tendency in a number of species of 
widely different relationships to follow similar lines of variation, 
thus affording a hint of some broad influence operating in the flora 
of the island. 
The reduced stature of arboreal species on a wind-swept island " 
may be readily understood and is doubtless correlated with an 
increased horizontal growth of the branches and their develop- 
ment low on the trunk, or from its base, which is a frequent con- 
dition of Nantucket trees. 
In the herbaceous species which show obvious departures from 
their usual forms tt seems possible to recognize a drift of variation 
in two main directions, one towards an increased development of 
pubescence, the other leading to a tendency in certain erect or 
ascending species to become declined or even prostrate. 
The Nantucket gooseberry is a marked example of a species 
modified by an unusual development of pubescence. In its ex- 
treme form the young branches, petioles, and lower leaf surfaces 
are densely white-tomentose and the upper surfaces of the leaves 
closely soft-pubescent. This increased pubescence often extends 
to the flowers, which become notably villous, and to the fruit, 
which is sometimes finely puberulent all over and may even de- 
