Volume Ii Part 35 (2/2)

You will blush with pleasure to hear that you are of some use to the master.

LETTER 666. TO J.D. HOOKER. [February, 1864?]

I shall write again. I write now merely to ask, if you have Naravelia (666/1. Ranunculaceae.) (the Clematis-like plant told me by Oliver), to try and propagate me a plant at once. Have you Clematis cirrhosa? It will amuse me to tell you why Clematis interests me, and why I should so very much like to have Naravelia. The leaves of Clematis have no spontaneous movement, nor have the internodes; but when by growth the peduncles of leaves are brought into contact with any object, they bend and catch hold. The slightest stimulus suffices, even a bit of cotton thread a few inches long; but the stimulus must be applied during six or twelve hours, and when the peduncles once bend, though the touching object be removed, they never get straight again. Now mark the difference in another leaf-climber--viz., Tropaeolum: here the young internodes revolve day and night, and the peduncles of the leaves are thus brought into contact with an object, and the slightest momentary touch causes them to bend in any direction and catch the object, but as the axis revolves they must be often dragged away without catching, and then the peduncles straighten themselves again, and are again ready to catch. So that the nervous system of Clematis feels only a prolonged touch--that of Tropaeolum a momentary touch: the peduncles of the latter recover their original position, but Clematis, as it comes into contact by growth with fixed objects, has no occasion to recover its position, and cannot do so. You did send me Flagellaria, but most unfortunately young plants do not have tendrils, and I fear my plant will not get them for another year, and this I much regret, as these leaf-tendrils seem very curious, and in Gloriosa I could not make out the action, but I have now a young plant of Gloriosa growing up (as yet with simple leaves) which I hope to make out. Thank Oliver for decisive answer about tendrils of vines. It is very strange that tendrils formed of modified leaves and branches should agree in all their four highly remarkable properties. I can show a beautiful gradation by which LEAVES produce tendrils, but how the axis pa.s.ses into a tendril utterly puzzles me. I would give a guinea if vine-tednrils could be found to be leaves.

(666/2. It is an interesting fact that Darwin's work on climbing plants was well advanced before he discovered the existence of the works of Palm, Mohl, and Dutrochet on this subject. On March 22nd, 1864, he wrote to Hooker:--”You quite overrate my tendril work, and there is no occasion to plague myself about priority.” In June he speaks of having read ”two German books, and all, I believe, that has been written on climbers, and it has stirred me up to find that I have a good deal of new matter.”)

LETTER 667. TO J.D. HOOKER. Down, June 2nd [1864].

You once offered me a Combretum. (667/1. The two forms of shoot in C.

argenteum are described in ”Climbing Plants,” page 41.) I having C.

purpureum, out of modesty like an a.s.s refused. Can you now send me a plant? I have a sudden access of furor about climbers. Do you grow Adlumia cirrhosa? Your seed did not germinate with me. Could you have a seedling dug up and potted? I want it fearfully, for it is a leaf-climber, and therefore sacred.

I have some hopes of getting Adlumia, for I used to grow the plant, and seedlings have often come up, and we are now potting all minute reddish-coloured weeds. (667/2. We believe that the Adlumia which came up year by year in flower boxes in the Down verandah grew from seed supplied by Asa Gray.) I have just got a plant with sensitive axis, quite a new case; and tell Oliver I now do not care at all how many tendrils he makes axial, which at one time was a cruel torture to me.

LETTER 668. TO J.D. HOOKER. Down, November 3rd [1864].

Many thanks for your splendid long letter. But first for business.

Please look carefully at the enclosed specimen of Dicentra thalictriformis, and throw away. (668/1. Dicentra thalictrifolia, a Himalayan species of Fumariaceae, with leaf-tendrils.) When the plant was young I concluded certainly that the tendrils were axial, or modified branches, which Mohl says is the case with some Fumariaceae.

(668/2. ”Ueber den Bau und das Winden der Ranken und Schlingpflanzen.

Eine gekronte Preisschrift,” 4to, Tubingen, 1827. At page 43 Mohl describes the tips of the branches of Fumaria [Corydalis] clavicualta as being developed into tendrils, as well as the leaves. For this reason Darwin placed the plant among the tendril-bearers rather than among the true leaf-climbers: see ”Climbing Plants,” Edition II., 1875, page 121.) You looked at them here and agreed. But now the plant is old, what I thought was a branch with two leaves and ending in a tendril looks like a gigantic leaf with two compound leaflets, and the terminal part converted into a tendril. For I see buds in the fork between supposed branch and main stem. Pray look carefully--you know I am profoundly ignorant--and save me from a horrid mistake.

LETTER 669. TO J.D. HOOKER.

(669/1. The following is interesting, as containing a foreshadowing of the chemotaxis of antherozoids which was shown to exist by Pfeffer in 1881: see ”Untersuchungen aus dem botanischen Inst.i.tut zu Tubingen,”

Volume I., page 363. There are several papers by H.J. Carter on the reproduction of the lower organisms in the ”Annals and Magazine of Natural History” between 1855 and 1865.)

Down, Sunday, 22nd, and Sat.u.r.day, 28th [October, 1865].

I have been wading through the ”Annals and Mag. of N. History.” for last ten years, and have been interested by several papers, chiefly, however, translations; but none have interested me more than Carter's on lower vegetables, infusoria, and protozoa. Is he as good a workman as he appears? for if so he would deserve a Royal medal. I know it is not new; but how wonderful his account of the spermatozoa of some dioecious alga or conferva, swimming and finding the minute micropyle in a distinct plant, and forcing its way in! Why, these zoospores must possess some sort of organ of sense to guide their locomotive powers to the small micropyle; and does not this necessarily imply something like a nervous system, in the same way as complemental male cirripedes have organs of sense and locomotion, and nothing else but a sack of spermatozoa?

LETTER 670. TO F. HILDEBRAND. May 16th, 1866.

Since writing to you before, I have read your admirable memoir on Salvia (670/1. ”Pringsheim's Jahrbucher,” Volume IV., 1866.), and it has interested me almost as much as when I first investigated the structure of orchids. Your paper ill.u.s.trates several points in my ”Origin of Species,” especially the transition of organs. Knowing only two or three species in the genus, I had often marvelled how one cell of the anther could have been transformed into the moveable plate or spoon; and how well you show the gradations. But I am surprised that you did not more strongly insist on this point.

I shall be still more surprised if you do not ultimately come to the same belief with me, as shown by so many beautiful contrivances,--that all plants require, from some unknown cause, to be occasionally fertilised by pollen from a distinct individual.

(PLATE: FRITZ MULLER.)

2.XI.II. CORRESPONDENCE WITH FRITZ MULLER, 1865-1881.

(671/1. The letters from Darwin to Muller are given as a separate group, instead of in chronological sequence with the other botanical letters, as better ill.u.s.trating the uninterrupted friends.h.i.+p and scientific comrades.h.i.+p of the two naturalists.)

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