WCP7055

[1]

Godalming, England

Sept. 15th. 1888.

T. F. Cheeseman Esq.

My dear Sir

Many thanks for sending me your paper as on the Flora of the Kermadec Islands, and for your letter. I quite agree with your general conclusions — except in one point, on which as yet all botanist are against me, & yet on which I feel convinced that I am right! It is as to the agency of the wind in the dispersal of seeds. There are large numbers of plants whose capsules open as soon as the seeds are ripe & scatter or drop their very small seeds — such as orchids, gentians, myrtles, scrophularinea &c. — which have no means [2] of dispersal either by flotation or by birds, except the very rare mode of being carried in wind as their feet. Yet some such plants occur in all oceanic islands, & I believe have few carried by wind. Not[?] by ordinary winds for which seeds with pappus a winged appendages[sic] are adapted, but by exceptional & violent storms, lasting for days, & whose power to carry objects quite as heavy as these small seeds is demonstrated. What seems to me to be forgotten is that such an event may be extremely rare & yet quite effective. After a volcanic island has been formed, a single seed carried (of a particular species) carried to [3] its once only in ten thousand years weight yet stock the island with that species if it fell on a favourable spot & was suited to the soil & surroundings, — whereas another plant may have its seeds carried every year, & yet never become established owing to the conditions — physical or organic — not being suitable. Facility of transmission is of very little importance, as in most cases possibility of transmission will do just as well. Are not[?] the seeds of the Wahlenbergia, Lobelia, Sacuolus[?], Veronica, & Orchidea such as must have been either directly by the wind, or in mud adhering to bird's feet? And is not the latter mode unlikely from the habits [4] of the plants? I think this subject is worth careful inquiry. I believe that small, light, flattened ^{or curved} seeds would be carried much farther, by exceptional gales, than feathered or hairy seeds, since the latter would collect moisture, have their down clotted, & then fall more rapidly. The great prevalence of ferns in oceanic islands is largely due to favourable conditions for growth — a moist ageeable[sic] climate, combined with the disadvantage many flowering plants have in the absence of insects suitable for cross fertilization. Fern spores, I believe, reach every spot in the globe, but only grow where conditions are favourable. If you would give us an exact description of the fruits & seeds ^{(size, weight, form, &c)} of all the Kermadec Is. plants, showing their adaptability for each possible wash[?] of transmission you would do a good work.

Believe me | yours faithfully | Alfred R. Wallace [signature]