agree in all their four highly remarkable
properties. I can show a beautiful gradation by which LEAVES produce
tendrils, but how the axis passes 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 ass 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