Letter icon
Letter 6428

Weale, J. P. M. to Darwin, C. R.

23 Oct 1868

    Summary Add

  • +

    Describes Lappago aleina, a species of South African grass,

  • +

    and reports his observations on locusts and their feeding habits.

Transcription

Bedford | Cape of Good Hope

23d. October 1868

My dear Sir

I have been waiting sometime with the hope of having something of interest to communicate to you, but am sorry to say that I have little to add to former communications.

Your last letter somehow or another went to Natal, & therefore did not come to hand till very late.

I was very much interested by what you wrote to me about the locust dung having grass seeds in it. The particular grass, to which I referred was ``Lappago aliena Spr.'' Its glumes are covered with minute hooked hairs, by which it adheres to the wool of sheep, & has become a very great nuisance to sheep farmers, by whom it is known here as the ``carrot seed'', to which it has a sort of analogical resemblance.

It generally springs up after rain, & is very sweet & much liked by the sheep as a pasture. Old farmers say that formerly it did not grow in the grass country, but was confined to the Karroo. I cannot however affirm this as correct, & I was suspicious about the authority for the following reason.

Cape wool was formerly noted for its bad get up, & it is still in bad repute, but about two years ago the London brokers complained very much about the appearance of the `Carrot seed' in the staple, & the attention of the farmers was directed to it. As a rule farmers only observe plants which in some way affect their pockets, & it was then that I was told that this seed had only been noticed since the last influx of locusts. One thing is quite certain that Karroo grasses of late, as also many Karroo shrubs such as `Chrysocoma tenuifolia' have spread into the sweet grass country, & many sweet grasses into the sour grass country on the coast. Last year, while riding from this to Kaffraria I particularly noticed the manner in which this grass had in places sprung up amongst the sour grasses, as also another kind—I think a `Festuca'—but am not certain—along the road sides throughout Kaffraria, although but seldom found in the sour grass itself. This last species is the principal pasture for sheep on which they thrive better than any other kind, & is the characteristic grass of the sweet grass country.

I have been able to watch the locusts very carefully as we have this last year had the largest swarms, which have been known for a long time

When the old ones came down last March, it was astonishing to see the destruction they caused throughout all the sweet grass country. Although large flights passed over this village very few remained here, as the pasturage just in the vicinity is rank, coarse & sour, but at about 12 miles from here they committed great havoc on a farm belonging to Mr. Fuller, one of the principal sheep farmers near here.

They appeared on the wing at about 9 am, & never left the farm but were constantly arriving till sundown. Both the ground & the air was dense with them. After the fine rains the whole farm was a waving field of grass in the morning studded here & there with the ``Acacia horrida'', & the pasturage intermixed with a few Karroo bushes, such as Chrysocoma, Melolobium, Pentzia &c  On the rises are little valleys rather densely covered with bushes of different kind, & there the grass was up to ones middle. The next day almost every patch of sweet grass had been cleared out, & large spaces of bare ground had taken the place of a luxuriant meadow.

The locusts are I think without exception more cunning than any kind of insect, excepting ``Hemiptera''. If the wind be not blowing at the time you may ride through a large swarm, as dense as a a heavy snow storm, & yet hardly one will touch you.

If, when they have just risen on the wing, a strong wind springs up they will travel a very long distance without stopping, but if once settled to feed they are exceedingly difficult to move, & care very little about smoke or fire. Towards night, when settled, they present a most singular appearance, & are a characteristic of a very weird landscape. One evening I observed them with the setting sun shining full over the plain. Every shrub & bush was covered with them, & immense heaps were congregated wherever they could get shelter.

The silvery light on their wings, & the reddish earthy tint of their bodies had a most singular aspect, as if all the trees were covered with a half smothered living fire, & I regretted that I was unable to sketch the scene. I tried to photograph a swarm which settled here in the village but the plate turned out a failure owing to the constant motion. I send you a copy of it such as it is.

The old ones invariably fly towards the sea, but never except in very strong winds, venture as far. The young on the contrary, as soon as hatched, seem instinctively to begin hopping inland. At the present time the whole country is alive with these young pests. It is curious to notice the predilection the locusts have for certain kinds of food. Where they can secure plenty of sweet grass, they seldom touch the crops, but when the former is scarce they clear a crop in a very short time.

In eating both the grass & the corn they climb up the stalks & devour the grain or bite it off so that it falls to the ground. I have seen whole crops of wheat & oats thus destroyed. Leguminous plants they generally avoid, & I have seen a garden in which the peas & beans were untouched although every other vegetable had been destroyed.

I have been told though I have never myself observed it that in a narrow valley, where they had cleared everything else they even attacked the foliage of the Blue Gum, notwithstanding its strong & peculiar odour & taste.

Since I last wrote I noticed a curious instance of irritability of stamens, in ``Schizanthus purpureus'' which I noticed whilst growing in my friend Mr. MacOwans Garden at Grahamstown. We were talking on the subject, when I said ``Let us try this plant, it looks a likely subject,'' & were much interested by the result. As I was there only a day I was unable to give the subject a closer examination.

Near King Williamstown I observed in last February a great many striped mules belonging to the Commissariat, one especially its legs were regularly barred from the hoof up to the haunches & the stripes inside the leg were as distinct almost as a zebra's only of a different colour.

``Queries about Expression''

1. A Kafir girl on hearing the price of an article, raised her eyebrows, & at the same time whistled, just as a European might.

4. The hand placed over the mouth in a contemplative manner, the head bent & eyes deflected down.

I had an opportunity of writing to Herr Mauch, when he was at D'Urban, Natal prior of his departure for the interior, & sent him a copy of your questions asking him particularly to make observations on the subject on interior natives, thinking that they would be of great value to you. He has promised to give his close attention to the subject. I also sent a copy to the Natal Natural History Society through Mr. Sanderson, the well known botanical collector.

I am very busy drawing & dissecting all the orchids I can lay my hands on, & any rare plants, by which means I hope we may someday be able to continue the Thesaurus, which Dr. Harvey's death has closed.

I must thank you very much for your photograph which I esteem very much, & enclose you mine as requested. I have not yet seen your new work but hope shortly to receive it, & look forward to it with great interest.

Meanwhile Believe me, my dear Sir | faithfully Yours | J. P Mansel Weale

    Footnotes Add

  • +
    f1 6428.f1
    The most recent extant letter from Weale is that of [10 December 1867] (Correspondence vol. 15).
  • +
    f2 6428.f2
    The most recent extant letter to Weale is that of 23 January [1868].
  • +
    f3 6428.f3
    A small packet of locust dung was enclosed with the letter from Weale of 7 July 1867 (Correspondence vol. 15). In his letter to Weale of 9 December [1867] (ibid.), CD reported that he had found seeds in the dung. CD had sown the seeds and sent the grasses to Joseph Dalton Hooker for identification; for Hooker's replies, see the letter to J. D. Hooker, [20 May 1868], n. 3, and the letter from J. D. Hooker, 22 June 1868. CD reported on his experiment in Origin 5th ed., p. 439.
  • +
    f4 6428.f4
    It had been suggested to Weale that locusts might disseminate `certain obnoxious grasses' (see Correspondence vol. 15, letter from J. P. M. Weale, 7 July 1867, where the phrase is mistranscribed as `certain obnoxious masses'). A modern synonym for Lappago aliena is Tragus racemosus, the large carrot-seed grass (G. E. G. Russell et al. 1990, pp. 337--9).
  • +
    f5 6428.f5
    Chrysocoma tenuifolia, or bitterbush, is indigenous to the more arid Karoo (or Karroo) and is still considered an invasive plant in the south-eastern grasslands of South Africa; Tragus racemosus, unpalatable to livestock, has also invaded overgrazed grasslands (Huntley ed. 1989, pp. 113--14, 215). The Great Karoo lay inland, to the west of Bedford.
  • +
    f6 6428.f6
    Tragus racemosus is often found on disturbed ground such as roadsides. There are eight indigenous species of Festuca in South Africa, as well as an introduced species that thrives on disturbed ground. See G. E. G. Russell et al. 1990, pp. 168--71, 337. `Kaffraria' initially comprised south-eastern territories colonised by the Portuguese and British, but by the mid nineteenth century indicated a more limited area that had come to be inhabited by the Xhosa people (EB).
  • +
    f7 6428.f7
    The brown locust (Locustana pardalina) swarmed Cape Colony from 1862 to 1876, coming from the Karoo, further inland (Fuller ed. 1907, p. 54; see also Faure 1932). Mr Fuller has not been identified.
  • +
    f8 6428.f8
    Two Melobium species and six Pentzia species indigenous to the Karoo still persist in South African grasslands that are used for grazing (see Wells et al. 1986, pp. 352, 403--6).
  • +
    f9 6428.f9
    The photograph has not been found in the Darwin Archive--CUL.
  • +
    f10 6428.f10
    Schizanthus purpureus has not been identified. Schizanthus is a genus native to Chile. On the significance of `irritability of stamens', see Correspondence vol. 13, letter from George Henslow, 6 November 1865 and n. 7. Weale refers to Peter MacOwan.
  • +
    f11 6428.f11
    CD recorded similar observations by others in Variation 2: 42. Weale had not yet received his copy of Variation (see n. 18, below).
  • +
    f12 6428.f12
    For CD's printed list of queries about expression, see Correspondence vol. 16, Appendix V.
  • +
    f13 6428.f13
    CD cited Weale for this observation in Expression, p. 286. The term `Kafir' was used to refer to the Xhosa people of south-eastern Africa.
  • +
    f14 6428.f14
    CD cited Weale for this observation in Expression, p. 230.
  • +
    f15 6428.f15
    There is no record of correspondence between CD and Karl Gottlieb Mauch; CD did not cite him in Expression.
  • +
    f16 6428.f16
    Weale probably refers to the Natal Agricultural and Horticultural Society, of which John Sanderson was president (Gunn and Codd 1981).
  • +
    f17 6428.f17
    Weale refers to William Henry Harvey's Thesaurus Capensis: or, illustrations of the South African flora (Harvey 1859--63).
  • +
    f18 6428.f18
    Weale refers to Variation. Weale's photograph has not been found in the Darwin Archive--CUL.
Maximized view Print letter