444 LETTEES TO DARWIN, 1843-1859 
suspension of the sporules of this genus in the air and the 
consequent strengthening of my hypothesis, that the genus 
should be decimated sparing only every tenth ! Of course 
it is a strong fact for migration, and for the existence of the 
impalpable spawn of Fungi, &c., in all air. 
I have been more coolly analysing the bearings of the 
Forbes Botanical question ^ lately, and with the distressing 
result, that I fear I must haul out of all participation with 
him. You will think me unstable as water, and I must 
blame myself for speaking too much without thinking. It 
is not from a reconsideration of liis facts and arguments 
that my faith is weakened, but from an independent exami- 
nation of the Flora of the N. Atlantic Isles and W. U. 
Kingdom, which shows that there are plants in those regions 
which have been more put to in getting there than the 
Asturias ones need have been. Such are the American 
plants, Eriocaulon septangulare in the Hebrides and W. 
Ireland, American Neottia in S. Ireland, and Trichomanes 
brevisetuni in W. Ireland and Madeira, all of them American 
plants not found further E. on continents of Europe or 
Africa. Also the Gymnogramma Totta, a fern of the Cape 
only in IMadeira and Azores, and Myrsine africana, which 
positively skips from the Cape across all intermediate 
Africa on one side to Abyssinia and on the other to the 
Azores ! I hope to be allowed a conversation with Forbes 
on the subject, for really with his Sargassum weed, &c., he 
is going too far. 
It is very easy to explain on what sort of ground Botanists 
make one class of plants higher, and as easy to prove them 
futile by their results. I do not however think your objection 
valid, urged on the grounds of Owen's observations on 
organs which are developed in the animal kingdom,^ but 
v>^hich organs are valueless for systematic purposes, if present 
even, in the vegetable. It is upon the modifications of the 
* Viz., that several Spanish plants in Ireland could not have been trEns- 
ported by any known agencies ; hence they supported the argument for a 
Miocene continental extension between Ireland and Spain, and from Spain to 
the N. Atlantic Islands. 
2 A. St. Hilaire used a multiplicity of parts — e.g. several circles of stamens, 
as evidence of the highness of the Ranunculaceae : Owen conversely used the 
same argument to show the lowness of some animals, urging that the fewer 
the number of any organ by which the same end is gained, the higher the animal. 
The subject of ' high ' and ' low ' is touched upon further, pp. 460, 463. 
