BICKNELL: FERNS AND FLOWERING PLANTS OF NANTUCKET 455 
on Manhattan Island as well as in similar situations in Connecticut, 
New Jersey, and Pennsylvania. A number of years ago this plant 
was made the subject of careful study by Doctor Britton and 
myself and we could then reach no other conclusion than that it 
was an unrecognized species. Subsequently Doctor Britton con- 
sulted, at Paris, the type of Lamarck’s plant and was satisfied 
that it established the identity of our saxicolous species. 
A character of this plant (A. spicata), although not of primary 
import, nevertheless having a suggestive value, is the white woolly 
exposed surface of the ovary. By this the plant would seem to 
be allied to Amelanchier rotundifolia (Michx.) Roem. [A. sanguinea 
(Pursh) Lindl.], and additional evidence of such relationship is seen 
in the form taken occasionally by the leaves and in the pronounced 
close venation which they sometimes develop. Amelanchter nan- 
tucketense, on the other hand, is undoubtedly in closer relationship 
with Amelanchier oblongifolia and, like that species, has the top of 
the ovary nearly or quite glabrous. Both are to be found growing 
together on Nantucket, displaying contrasts of leaf and flower 
which I do not think have been given undue recognition in the dis- 
position here made of the new plant. A Juneberry collected in 
a bog at Long Pond, Aug. 12, 1906, growing with this species and 
with A. oblongifolia, appears to be intermediate between them 
and is quite probably a hybrid. 
CRATAEGUS 
It appears that, instead of a single species of white thorn, which 
it has been supposed was the sole representative of its group native 
on Nantucket, four or quite possibly five native species belong to 
the island’s flora. One of these, Crataegus pruinosa (Wendl.) 
C. Koch, grows also on Tuckernuck Island and on Chappaquiddick 
Island, Marthas Vineyard; another, Crataegus chrysocarpa Ashe, 
of which only a single shrub was met with on Nantucket, is on 
Marthas Vineyard rather frequent; still another, Crataegus Bick- 
nellii Eggleston, frequent on Nantucket, is not known to occur 
anywhere else. The comparison is interesting, that of four species 
collected on Marthas Vineyard two have not been found on 
Nantucket, one of which, Crataegus schizophylia Eggleston, is, so 
far as we now know, endemic on Marthas Vineyard, paralleling 
