Chapter 358

I hope that you may find time to go on with your experiments on such plants as Lagerstroemia, mentioned in your letter of October 29th, for I believe you will arrive at new and curious results, more especially if you can raise two sets of seedlings from the two kinds of pollen.

Many thanks for the facts about the effect of rain and mud in relation to the waxy secretion. I have observed many instances of the lower side being protected better than the upper side, in the case, as I believe, of bushes and trees, so that the advantage in low-growing plants is probably only an incidental one. (693/1. The meaning is here obscure: it appears to us that the significance of bloom on the lower surface of the leaves of both trees and herbs depends on the frequency with which all or a majority of the stomata are on the lower surface--where they are better protected from wet (even without the help of bloom) than on the exposed upper surface. On the correlation between bloom and stomata, see Francis Darwin "Linn. Soc. Journ." XXII., page 99.) As I am writing away from my home, I have been unwilling to try more than one leaf of the Passiflora, and this came out of the water quite dry on the lower surface and quite wet on the upper. I have not yet begun to put my notes together on this subject, and do not at all know whether I shall be able to make much of it. The oddest little fact which I have observed is that with Trifolium resupinatum, one half of the leaf (I think the right-hand side, when the leaf is viewed from the apex) is protected by waxy secretion, and not the other half (693/2. In the above passage "leaf" should be "leaflet": for a figure of Trifolium resupinatum see Letter 740.); so that when the leaf is dipped into water, exactly half the leaf comes out dry and half wet. What the meaning of this can be I cannot even conjecture. I read last night your very interesting article in "Kosmos" on Crotalaria, and so was very glad to see the dried leaves sent by you: it seems to me a very curious case. I rather doubt whether it will apply to Lupinus, for, unless my memory deceives me, all the leaves of the same plant sometimes behaved in the same manner; but I will try and get some of the same seeds of the Lupinus, and sow them in the spring. Old age, however, is telling on me, and it troubles me to have more than one subject at a time on hand.

(693/3. In a letter to F. Muller (September 10, 1881) occurs a sentence which may appropriately close this series: "I often feel rather ashamed of myself for asking for so many things from you, and for taking up so much of your valuable time, but I can assure you that I feel grateful.")

2.XI.III. MISCELLANEOUS, 1868-1881.