326 DR. HOOKER ON THE DISTRIBUTION OF ARCTIC PLANTS. 
according to the different views of botanists. Thus P. Vahliana, L., is the nivea var. j 
of Torrey and Gray, and includes Jamesoniana, Grev. P. pulchetta, Br., is a very arctic 
form, and according to Brown is Greville's sericea, L., between which plant and nivea it 
appears quite intermediate ; all depends upon what arbitrary character is assumed to be 
the diagnostic one. 
P. Keilhauii, Sommf. Of this I know nothing ; Nyman doubtfully refers the Spitz- 
bergen plant of this name to Brown's pulchella. P. frigida ? Grev., is referred here by 
Brown, and by Torrey and Gray under Vahliana, L., /3, which is also the P. Groenlandica, 
Br., of the same authors. 
P. frigida, Vill. I am quite puzzled with this. Arctic American and Greenland speci- 
mens seem to connect P. minima, Hall. {Brauniana, Hoppe), glacialis, Hall., and nana, 
Lehm. The United States plant, found only on the White Mountains (P. Robbinsiana, 
Oakes), is referred to minima |3 by Torrey and Gray, and afterwards to frigida, Vill., by 
Gray, who observes that the European minima is probably a variety. The Danish au- 
thorities refer the Greenland and Labrador plant to P. emarginata, Pursh {nana, Lehm.), 
whilst both Asa Gray and Durand refer it to frigida, Vill. I cannot help suspectin 
that P. elegans, C. & S., of Eastern Siberia, is the same thing, and that all will be 
found to inosculate with the varieties or forms of P. verna. I have confirmed Torrey 
and Gray's conjecture regarding nana, Lehm., being the same with emarginata, Pursh. 
P. verna, L. Under this, as one collective species or group of subspecies and varieties, 
I have introduced five North European arctic and alpine plants, whose forms inosculate 
perplexingly. The typical P. verna is not Lapponian, according to Eries ; and none of its 
included forms occur anywhere in N.E. America, except Labrador and Greenland (as- 
suming that biflora is distinct as a species). P. aurea, L., is distinguished by Koch by 
its leaves silvery beneath ; the aurea of Smith he refers to alpestris, Hall. I find this 
character to be very variable. P. crocea, Schl., is referred by Koch to a variety of alpestris ; 
he has, however, a var. crocea of verna. P. maculata, Lehm., is, together with aurea 
and crocea, referred to Salisburgensis by Torrey and Gray. — P. Salisburgensis, Hsenke, is 
regarded by Koch as a synonym of alpestris. Ruprecht, who observes that Salisburgensis 
is found throughout the arctic Island of Kolgujew, says that it is the same with verna, L-, 
genuina." P. alpestris, 1 L all . : this, which is a much larger-flowered plant than the 
c< 
ordinary verna, and otherwise different in habit, is kept distinct by Eries. Koch also 
distinguishes it from verna by its habit and ovate stipules, and from aurea by the leaves 
not silvery beneath. Bentham regards both aurea and alpestris as luxuriant forms of 
verna. Watson suggests that the distribution of verna, alpestris, and Salisburgensis 
should be treated in Great Britain as that of one plant. 
Eragaria vesca, L. I have adopted the conclusions of J. Gay (Ann. Sc. Nat. ser. 4. 
vol. viii. p. 196) for the distribution of this plant, but very much suspect that it would 
have been more consistent to have (for distributional purposes) included that of cottina, 
Ehr., canadensis, Mich., and Chilensis, Ehr., under it. 
Sanguisoeba officinalis, L. The four species brought under this vary very much ; and I 
doubt if the majority will ever rank above local or permanent varieties. S. officinalis itselt is 
