DR. HOOKER ON THE DISTRIBUTION OF ARCTIC PLANTS. 333 
includes under it glabratus, Hook. For my own part, I find it impossible to separate the 
forms of acris from those of alpinus, and am rather disposed to refer this to the former. 
E. wii/lorus,' L. This is E. alpinus (3 of Ledebour, and alpinus y of De Candolle, and 
is united with alpinus by Bentham. also. According to Fries, who unites pulchellus, DC, 
with it as a variety, it is a good species. I cannot regard it otherwise than as an arctic and 
alpine state of alpinus, with a more woolly involucre, fewer capitula, and better- developed 
inner-ray florets. I find all intermediate forms. 
E. purpureas, Ait., is included under Philadelphicus by Torrey and Gray, &c. 
Taraxacum Dens-leonis, Desf. Fries adopts the name officinale, Weber, and includes 
palustre as a variety, both being Lapponian, in which Watson, Koch, and most botanists 
coincide. T. ceratophorum is rather a form with an over-developed condition of the invo- 
lucral scales, than a variety properly so called. 
T. Scorzonera, Heich., from Arctic Siberia (Flor. Taimyr.), is not included in Ledebour' s 
1 Flora Rossica,' 
T. plnjmatocarptim, J. Valil, Flor. Dan. 2298, found in Arctic Greeland only, is a small 
form with the habit aud involucre of T. palustre, Sm., and shorter achenia than is usual 
in the genus. * 
Sonchus maritimns, L., is kept distinct by Koch, but included by Fries as a variety of 
arvensis. 
Leoxtodon autumnalis, L. I am obliged to regard Keretinus, NyL, as the same with 
autumnalis, because Ball (Ann. Nat. Hist. 1850, p. 2) observes that the character of erect 
and drooping capitulum (on which this species appears founded) is not to be relied on in 
other species of the genus. I have never seen copious specimens of this L. Keretinus, 
which Ball omits in his otherwise very full account of the genus (/. <?.). Fries regards it 
as a not yet fully developed species. Ledebour puts it in another section of the genus. 
Koch makes L. Taraxaci, L. {Apargia, Smith), a variety of autumnalis', and Watson 
says that the British Taraxaci graduates insensibly into autumnalis. Ball makes it a 
synonym. Fries introduces under autumnalis a variety nigro-la nation ; he describes both 
as being common throughout Lapland. 
HiEiiACiuM. I have grouped the various arctic forms discriminated by Fries, into a 
few aggregate species, such as are recognized by Arnott, Bentham, Watson, &c. 
Satjssurea alpina, L. I have treated this as an aggregate species, because S. nuda, mon- 
ticola, and angustifolia all seem to graduate into it, and several of them into one another 
I should not be surprised if 8. subsinuata, which is hitherto known from one locality 
only, proved still another form of the same variable plant. 
Carditis crispus, L. This attains a higher latitude than C. acanthoicles, L., of which • 
Bentham and others consider it a variety. The two certainly pass into one another. 
Campanula Imifolia, Hamke, ana Scfieuzeri, Vill., are certainly referable to C. rotundi- 
folia, as held by Linnseus and most modern authors, though Scheuzeri is regarded by Fries 
distinct 
2x2 
