From Daniel Oliver 25 September 1860
My results so far with pure gum quite support your opinion.1 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 2 I think of, as one, the Flora (Florula!) of Aden upon wh. Dr. Anderson is just now engaged here.3 It is to appear in a supplt. to the Linn: Journal It is a very spiny Flora. Then Delile, for Egypt.4 perhaps Kelaart, for Gibraltar.5 Munby’s list for Algeria—6 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)7—V. Diemen’s Land. (J.D.H.)8 So. United States (Chapman).9 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.—10
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”11
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!12
His results with pure gum on Drosera spathulata entirely support CD’s opinion. Other observations on insectivorous plants.
Please cite as
Darwin Correspondence Project, “Letter no. 2927,” accessed on 25 July 2016, http://www.darwinproject.ac.uk/DCP-LETT-2927