, it is always the central or sub-central flower; but what is
far more curious, the nectary, which is blended with the peduncle of
the flowers, gradually lessens and quite disappears (588/1. This fact
is mentioned in Maxwell Masters' "Vegetable Teratology" (Ray Society's
Publications), 1869, page 221.), as the dark shade on the two upper
petals disappears. Compare the stalk in the two enclosed parcels, in
each of which there is a perfect flower.

Now, if your gardener will not be outrageous, do look over your
geraniums and send me a few trusses, if you can find any, having the
flowers without the marks, sending me some perfect flowers on same
truss. The case seems to me rather a pretty one of correlation of
growth; for the calyx also becomes slightly modified in the flowers
without marks.

LETTER 589. TO MAXWELL MASTERS. Down, April 7th [1860].

I hope that you will excuse the liberty which I take in writing to you
and begging a favour. I have been very much interested by the abstract
(too brief) of your lecture at the Royal Institution. Many of the facts
alluded to are full of interest for me. But on one point I should be
infinitely obliged if you could procure me any information: namely, with
respect to sweet-peas. I am a great believer in the natural crossing of
individuals of the same species. But I have been assured by Mr. Cattell
(589/1. The nurseryman he generally dealt with.), of Westerham, that the
several varieties of sweet-pea can be raised close together for a number
of years without intercrossing. But on the other hand he stated that
they go over the beds, and pull up any false plant, which they very
naturally attribute to wrong seeds getting mixed in the lot. After many
failures, I succeeded in artificially crossing two varieties, and the
offspring out of the same pod, instead of being intermediate, was very
nearly like the two pure parents; yet in one, there was a trace of the
cross, and these crossed peas in the next generation showed still more
plainly their mongrel origin. Now, what I want to know is, whether there
is much variation in sweet-peas which might be owing to natural crosses.
What I should expect would be that they would keep true for many years,
but that occasionally, perhaps at long intervals, there would be a
considerable amount of crossing of the varieties grown close together.
Can you give, or obtain from your father, any information on this head,
and allow me to quote your authorit