, as in Lobelia,
each flower must be fertilised by pollen from another and earlier
flower.

How curious that the indusium should first so cleverly collect pollen
and then afterwards push it out! Yet how closely analogous to Campanula
brushing pollen out of the anther and retaining it on hairs till the
stigma is ready. I am going to try whether Campanula sets seed without
insect agency.

LETTER 591. TO J.D. HOOKER.

(591/1. The following letters are given here rather than in
chronological order, as bearing on the Leschenaultia problem. The latter
part of Letter 591 refers to the cleistogamic flowers of Viola.)

Down, May 1st [1862].

If you can screw out time, do look at the stigma of the blue
Leschenaultia biloba. I have just examined a large bud with the indusium
not yet closed, and it seems to me certain that there is no stigma
within. The case would be very important for me, and I do not like to
trust solely to myself. I have been impregnating flowers, but it is
rather difficult...

I have just looked again at Viola canina. The case is odder: only 2
stamens which embrace the stigma have pollen; the 3 other stamens have
no anther-cells and no pollen. These 2 fertile anthers are of different
shape from the 3 sterile others, and the scale representing the
lower lip is larger and differently shaped from the 4 other scales
representing 4 other petals.

In V. odorata (single flower) all five stamens produce pollen. But I
daresay all this is known.

LETTER 592. TO J.D. HOOKER. November 3rd [1862].

Do you remember the scarlet Leschenaultia formosa with the sticky margin
outside the indusium? Well, this is the stigma--at least, I find the
pollen-tubes here penetrate and nowhere else. What a joke it would be if
the stigma is always exterior, and this by far the greatest difficulty
in my crossing notions should turn out a case eminently requiring insect
aid, and consequently almost inevitably ensuring crossing. By the
way, have you any other Goodeniaceae which you could lend me, besides
Leschenaultia and Scaevola, of which I have seen enough?

I had a long letter the other day from Crocker of Chichester; he has the
real spirit of an experimentalist, but has not done much this summer.

LETTER 593. TO F. MULLER. Down, April 9th and 15th [1866].

I am very much obliged by your letter of February 13th, abounding with
so many highly interesting facts. Your account of the Rubiaceous plant
is one of the most ext