BICKNELL: FERNS AND FLOWERING PLANTS OF NANTUCKET 373 
PANICUM COLUMBIANUM Scribn. 
The var. thinium Hitche. & Chase is recorded from Nantucket 
in their North American Species of Panicum (p. 249), on the basis 
of specimens collected by me in 1899 and 1904. I have myself no 
clear conception of this plant. The specimens cited, and others 
since collected more or less similar, suggest aberrant forms of P. 
meridionale or of P. albemarlense. 
*PANICUM ORICOLA Hitchc. & Chase. 
*PANICUM ALBEMARLENSE Ashe. 
Earlier in this paper these grasses were included in P. merid- 
tonale. Transition between all three is, I think, perfectly ob- 
vious, but there is, nevertheless, the paramount fact that each 
in its true development upholds a well-defined type recognizable 
unmistakably everywhere in the field. We do not know that hy- 
bridization may not have been at work releasing the connecting 
forms but, however this may be, it would seem that a frank recog- 
nition of what nature has been careful to produce on an extensive 
scale must accept these closely related grasses as being essentially 
distinct. 
P. oricola is more especially confined to sterile sandy tracts 
often along shores. In damper soils among taller vegetation it 
develops elongated leafy culms and shows a marked departure 
from its usual habit. Certain examples difficult to assign have the 
appearance of being hybrids with P. meridionale, and occasional 
stout forms even suggest involvement with P. tsugetorum. 
P. meridionale is the most common and generally distributed 
of the three and abounds amid the low herbage of the plains and 
commons all over the island. A very small and delicate form of 
this species, if such it be, collected in dryish places along thickets 
in Tom Never’s Swamp is especially to be remarked. P. merid- 
tonale, like all of its local group, appears everywhere to be 
perfectly constant in its character of obviously pubescent spikelets. 
In this small form the spikelets are either quite lucid and glabrous 
or with a very few mostly basal or marginal hairs; the panicles 
are very small and few-flowered and, with the culms, less puberu- 
lent than in the species, or essentially glabrous. 
P. albemarlense more than the others passes into ambiguous 
