Ɛpsilon

From Fritz Müller   1 January 1882

Blumenau, Sa Catharina, Brazil

January 1st. 1882

My dear Sir!

I received last week your kind letter of Novbr. 13, in which you ask me the name of the plant, of which I sent you seeds some months ago. I must confess, that I do not remember well, what seeds they were, but I think they were those of our sensitive Mimosa; if so, you will see it as soon as the first leaves appear.1

In your “Movements of plants” (pg. 308) you say, that the cotyledons of Bauhinia (grandiflora) would probably have closed completely at night, if the seedlings had been kept in a warmer place, and to me also this appeared to be most probably.2 Now we have presently very hot weather, (about 25oC. at night, 30oC or more at noon), but the cotyledons of some very young seedings of Bauhinia grandiflora do not sleep at all!— In Bauhinia brasiliensis I observed lately a curious fact; in bright sunshine the two halves of the leaves rise up more or less, as they do also at night; now I met with a plant, which, after having been exposed for hours to the rays of the sun, had suddenly been overshadowed by a large tree and in this plant the two halves of the leaves had descended beneath the horizontal plan, which they use to form during the day, forming with the horizon angles varying from about 15o to nearly 45o.3 diagram

I enclosed some fresh seeds of a long-styled plant of Pontederia crassipes, which I had legitimately fertilised with pollen from the long stamens of mid-styled plants.4

Wishing you a very happy new year I am | dear Sir with the deepest respect | Yours very sincerely | Friz Mülller

1
The seeds were probably of Mimosa pudica (shame plant); Müller had sent flower heads with what CD described as ‘brown seeds somewhat sculptured on their sides’ (Correspondence vol. 29, letter to Fritz Müller, 13 November 1881).
2
See Movement in plants, p. 308; CD had described the plant as a ‘Bauhinia from St. Catharina in Brazil’. Müller evidently knew that the species was Bauhinia grandiflora (a synonym of B. aculeata subsp. grandiflora).
3
CD had reported, based on information from Müller (probably contained in a now missing section of the letter from Fritz Müller, 28 February 1881, Correspondence vol. 29), that the leaves of Bauhinia brasiliensis did not sleep (see ibid., letter to Nature, 14 April [1881]). The movement of the leaves upward was an example of movement CD had called paraheliotropism: movement of leaves during the day to reduce intense illumination (Movement in plants, p. 419). The downward movement was more typical of sleep (nyctitropic) movement. Müller discussed the movement of leaves in a brief notice in Kosmos, May 1882 (F. Müller 1882).
4
Müller had written to CD about heterostyly in Pontederia crassipes (a synonym of Eichhornia crassipes) and sent flowers in a now missing letter of 2 December 1881 (see letter to Fritz Müller, 4 January 1882). CD referred to crosses made using pollen of the same form of flower in dimorphic or trimorphic plant species as illegitimate, and those fertilised by pollen of a different form as legitimate (see ‘Three forms of Lythrum salicaria’, p. 186).

Please cite as “DCP-LETT-13593,” in Ɛpsilon: The Charles Darwin Collection accessed on 5 June 2025, https://epsilon.ac.uk/view/dcp-data/letters/DCP-LETT-13593