70 BICKNELL: FERNS AND FLOWERING PLANTS OF NANTUCKET 
DROSERA LONGIFOLIA L. 
Common in bogs and on pond shores. 
DRoSERA FILIFORMIS Raf. 
Common on the sandy shores of Tom Never’s Pond and spar- 
ingly near the head of the swamp. A single flower as late as 
Sept. 15, 1907. 
CRASSULACEAE 
TILLAEAstRUM VaiLiantil (Willd.) Britton. 
One of the rarer plants of which we have earliest record on 
Nantucket is the 77//aea simplex of Nuttall, which was recorded by 
William Oakes as having been collected by him in 1829 ‘‘ on the 
dried borders of small ponds” (Hovey’s Mag. 7: 182. 1841). 
Writing in 1888, Mrs. Owen says ‘‘ Not reported since.’ In the 
herbarium of the Nantucket Maria Mitchell Association and of 
the New York Botanical Garden are Nantucket specimens of the 
plant now referred to 72//aeastrum Vaillant (Willd.) Britton which 
were collected by Mrs. Mabel P. Robinson on the shore of Hum- 
mock Pond Aug. 15, 1894, and July, 1896. Mrs. Albertson has 
informed me that the plant still grows at that locality, having been 
collected there in very recent years. 
Whether 7i//aeastrum Vaillantii (Willd.) Britton is really dis- 
tinct from Zi/aeastrum aguaticum (L.) Britton (Tillaea simplex 
Nutt.) cannot yet be said to be satisfactorily established. The . 
only diagnostic character adduced for 7. Vai/lantii would seem to 
be the slender peduncle, but such a character might well prove to 
be an unstable one in a shore plant which is doubtless sometimes 
subject to submersion, and it remains to be determined whether the 
elongation of the peduncle is not related to a chance submersion of 
the plant during some period of its growth. In one of Mrs, Rob- 
inson’s Nantucket specimens the lower flowers only are peduncled, 
the uppermost being subsessile. 
Should the two plants be distinct, it is not improbable that 
both are to be credited to Nantucket and that Oakes was quite 
correct in his record of 7i//aea simplex, which plant, in its perfectly 
typical form, was collected on Marthas Vineyard, not twenty miles 
from Nantucket, on September 27, 1909. 
