DR. HOOKER ON THE DISTRIBUTION OF ARCTIC PLANTS. 313 
land ; Bentham would unite them all. The absence of any form in Greenland is a most 
remarkable fact, the common one being most abundant and conspicuous in Iceland. 
Delphinium Middendorffii. Trautvetter, the author of this species, indicates its affinii y 
with Menziesii, but does not appear to have compared it with that plant, which, judging 
from the figure of Trautvetter, may not be distinguished. Whether D. Memiesii itseli 
may not be the same with some better-known species, is a question for future deter- 
mination . 
B. intermedium, Ait., is elatum /3, Turc. (El. Baik. Dahur.). 
Aquilegia Canadensis, L. The very close affinity and probable identity of A. Cana- 
densis, L., and A.formosa, Eisch., is indicated in the 'Elora Indica;' and on re-examina- 
tion, with more specimens .of the former to compare, I find no reason for modifying that 
conclusion. 
A. brevistylis, Hook. Originally doubtfully referred by Richardson to A. vulgaris, L. ; 
the styles, however, which are somewhat variable in the European plant, are always much 
shorter in the American. It is a very northern species in America, and not hitherto 
known west of the Rocky Mountains, though I have seen specimens of a Sitka plant, in 
an indifferent state, which is a great deal like it. It is also allied to the Siberian A. 
parviflora, Led. 
Actlea spicata, L. The A. rubra, Willd., is referred to nigra by Fries, both being Lap- 
ponian. Asa Gray (in litt.) combines with them A. alba, Big., and arguta, Nutt. 
Papaver nudicaule is now almost universally regarded as specifically the same with 
alpinum, L. 
Eumaria officinalis, L., occurs sporadically throughout Nordland, according to Erics 
and Andersson, but can hardly, I think, be considered an indigenous plant. 
Nuphar luiea, L. This, together with the species enumerated under it, and N. ad- 
vena, Ait., are, perhaps, rather forms of one collective or aggregate species than perma- 
nent undistinguishable plants ; and it is further possible that the N. sagittafolia, Pursh, 
may be another state, in which the early sagittate form of leaf is retained in the adult 
plant. Torrey and Gray refer Kalmiana to lutea /3, and say of advetia that it is not 
specifically distinct. Asa Gray latterly keeps up advena and Kalmiana, but adds to the 
latter N. intermedia, Led. P Nyman and Ledebour keep all distinct. Watson, from his 
notes under pumila, seems to regard it with doubt. Eries keeps lutea and pumila di- 
stinct, but regards intermedia, Led., as a variety of lutea, and adds as a Lapland variety 
to pumila the Spenneriana, Gaud. Lastly, Koch keeps lutea, pumila, and Spenneriaua, 
all distinct ; and Bentham unites the two first together with intermedia and minima 
of Enarl. Bot. 
D 
& 
Barbarea vulgaris, Br. This, again, is either a collective species or several species 
variously discriminated. Eries distinguishes stricta, Er., vulgaris, Br. (including under 
it as a variety arcuata, Reich.), and precox, Sm. Nyman excludes precox, Br., from 
Scandinavia, and reduces precox, Sm., to arcuata. Watson finds himself compelled to 
