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Letter 2927

Oliver, Daniel to Darwin, C. R.

25 Sept 1860

    Summary Add

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    His results with pure gum on Drosera spathulata entirely support CD's opinion. Other observations on insectivorous plants.


Kew. W.

25th. IX/60

Dear Sir,

My results so far with pure gum quite support your opinion. Yesterdy. morng. 9.25. a drop was put on a leaf of D. spathulata (a leaf of wh. I enclose)    at 2.10 P.M. no marked change,—proby. some inflection of inner glands,—but the marginal patent or recurved. 5.55. do. this day (Tuesdy.) 8.56 AM & 5.48 P.M. No material change as yet. The plant looks unhealthy.

Another drop was placed on a leaf of D rotundifolia? 2.13. P.M. (Yestery.)— No marked result this eveng.

I must try the old gum again. I have not burnt it yet. Besides Im not sure if we used it (the new) in equally strong solution. I intend still trying it.

We have another Drosera    I dont know the species,—(I understand Australian) with narrow linear leaves    Its rate of incurving some days ago over a fly was as follows

abt [DIAG] —1st day. 3.— P.M. 2— 8.35. AM — — 2.40 P.M — — 6.13 P.M —3rd[UNDERLINE] day 8.30. am. 4th[UNDERLINE] day. morng. no mrkd. chge.

I quite look to working up one or two spinous Floras    I think of, as one, the Flora (Florula!) of Aden upon wh. Dr. Anderson is just now engaged here. It is to appear in a supplt. to the Linn: Journal    It is a very spiny Flora. Then Delile, for Egypt. perhaps Kelaart, for Gibraltar. Munby's list for Algeria— No. West India.—& Some part of Tropical Australia or Mexico would be important. To contrast I would take our own Flora,—that of Arctic circle (easy)—upon wh. Dr. H. has much material for the Linn Trans. (it will not appear tho` I doubt till towds. close of next year)—V. Diemen's Land. (J.D.H.)    So. United States (Chapman). Before setting seriously to work upon it I should like to complete a little task I have in hand among the Aurantiaceae wh. I am trying (apart from Citrus) to rearrange.—

The various sorts of spinosity ought to be separately tabulated,—whether true spines,—epidermal (prickles) & leaf appendages,—hardwd. bracts, &c    Often it will be difficult to draw the line between spinose & spineless species,—as among Thistles, Dipsacus, &c. &c.

Apropos of Drosera see a footnote in Dr. Bromfield's 'Flora Vectensis` p. 56—``The glands x x x x curving eventually over the flies x x x ensnared by their clammy exudation, but never, so far as I could observe, assisting primarily in their capture by any sudden contraction as in Dionæa muscipula''

I put a bit of paper in daubed with old gum,—   I did not perceive animal odour on burning a piece.

Very faithfully yours | Danl. Oliver. Jr

I doubt if we get good seed this autumn from over 3 or 4 of the isosceles beds!

    Footnotes Add

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    f1 2927.f1
    CD had suggested that the gum Oliver used in his first experiments on Drosera was perhaps contaminated with nitrogenous matter. See letters to Daniel Oliver, 21 [September 1860] and [22--3 September 1860].
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    f2 2927.f2
    See letter to Daniel Oliver, 24 [September 1860].
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    f3 2927.f3
    Thomas Anderson was working at the Royal Botanic Gardens, Kew, on the taxonomy of the flowering plants found in Aden (Anderson 1860). In 1861 he assumed the directorship of the Calcutta Botanic Gardens.
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    f4 2927.f4
    Alire Raffeneau-Delile described the Egyptian plants collected by members of the French Commission d'Egypt (Raffeneau-Delile [1813] and [1824]).
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    f5 2927.f5
    Edward Frederick Kelaart published a flora of Gibraltar in 1846 (Kelaart 1846).
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    f6 2927.f6
    Giles Munby lived in Algeria and published a flora of the native plants of the country in 1859 (Munby 1859).
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    f7 2927.f7
    Oliver refers to Joseph Dalton Hooker, who had read a paper on the `Outline of the distribution of Arctic plants' at a meeting of the Linnean Society of London on 21 June 1860. The paper was published in 1862 (Hooker 1862a).
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    f8 2927.f8
    Hooker 1855--60.
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    f9 2927.f9
    Alvan Wentworth Chapman was the author of a flora of the southern states of America (Chapman 1860).
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    f10 2927.f10
    Oliver published a study of the Aurantiaceae in 1861 (Oliver 1861).
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    f11 2927.f11
    Bromfield 1856.
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    f12 2927.f12
    See letter to Daniel Oliver, 15 [September 1860].
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