From J. D. Hooker [12 December 1843 – 11 January 1844]
his best friends.—
The Galapago plants are far more xtensive in number of species than I could have supposed, & are the foundation of an xcellent flora of that group: Mr Henslow as sent with them those of Macræ1 which hardly differ from yours— I was quite prepared to see the xtraordinary difference between the plants of the seperate Islands from your journal, a most strange fact.. & one which quite overturns all our preconceived notions of species radiating from a centre & migrating to any xtent from one focus of greater developement.
I do not think that there is in the North any instance of the floras of two such remote spots as Kerg. Land2 & Cape Horn being identical. Two Floras appear in the Northern Hemisphere, the American & the Europæan.— The former is confined to the American Arctic shores & Islands, the latter to all Arctic Europe Asia & Greenland:— Western Arctic America to the W. of the great chain of the Rocky Mts. & North of the Oregon River, may also belong to the Europæan flora & is likely to, but I have not compared, having no materials in the Erebus— The abrupt line of demarcation is most remarkable in Baffins Bay & Davis Straits, the most common Europæan Heathers & some other plants being found abundantly along the Eastern shores & Islands of those waters, but never on the Western— Of course a multitude of plants are common to both hemispheres, which makes it in one sense the more remarkable that two or three of the types of Northern Europæan Botany should not cross to the Westwd of Longit. 60 W.—
I have been progressing with the Antarctic plants, using your’s King’s & my own at once, & each according to the Nat. Ords.3 beginning with Ranunculaceæ,4 where the value of every scrap tells better than it is possible to suppose. The little Cardamine or cress I prove by a comparison with about 50 states of it, running through the whole continent of S. Am., to be the same as the most common Europæan weed C. hirsuta.5 This is not wonderful, but it is that the Winters’ Bark, Drimys Winteri, should xtend through the whole continent of S. America & Mexico, from 25 N to 56 S.— It is true that the xtreme states vary, & apparently specifically, but take the regular series of specimens, beginning with my own Cape Horn ones, your & King’s Fuegian, Bertero’s6 & Bridge’s, & Cuming’s Chilian, the Brazilian ones of many collectors; Peruvian & Bolivian states from others; & finally, end the list with the Mexican, & no one can (not even the most determined species monger) make them specifically distinct— It is further proved by the later Brazilian Botanial authors, considering their species the Chilian, & cotempora- neous Mexican writers not aware of this last reunion, uniting theirs to the Brazilian.— I do not suppose that there is another plant of so great a size having 1/3 as great a range in Latitude.— 7
The Govt have not as yet granted any thing towards my publication, but I hope they will ere long. Not being a a good arranger of xtended views I rather fear the Geographical distribution, which I shall not attempt until I have worked out all the species, especially as I hope that more facts of as great consequence as the range of the Winters’ bark may turn up.
I fear I may have tired you with my crude views on these subjects.
With many happy returns of this season | Believe my dear Sir | Yours most truly & obliged | Jos D Hooker.
We have just had a pretty little Barberry of your Chiloean collection engraved for the Icones Plantarum8 as it will not come into the Antarctic Flora, save in a note
Henslow has sent him CD’s Galapagos plants along with Macrae’s. JDH impressed by the island endemism, which "overturns all our preconceived notions" on centres of radiation. Describes the extent, and the sharp demarcation at longitude 60° W, of the American and European Northern Hemisphere floras. CD’s plants among those he is using to do Antarctic flora. Drimys winteri shows a graded series of states down the length of the South American continent.
Please cite as
Darwin Correspondence Project, “Letter no. 723,” accessed on 6 December 2016, http://www.darwinproject.ac.uk/DCP-LETT-723