or
crossing. The Fumariaceae offer a good instance of this, and Treviranus
threw this order in my teeth; but in Corydalis Hildebrand shows how
utterly false the idea of self-fertilisation is. This author's paper
on Salvia (694/1. Hildebrand, "Pringsheim's Jahrbucher," IV.) is really
worth reading, and I have observed some species, and know that he is
accurate]. (694/2. The passage within [] was published in the "Life
and Letters," III., page 279.) Judging from a long review in the "Bot.
Zeitung", and from what I know of some the plants, I believe Delpino's
article especially on the Apocynaea, is excellent; but I cannot read
Italian. (694/3. Hildebrand's paper in the "Bot. Zeitung," 1867, refers
to Delpino's work on the Asclepiads, Apocyneae and other Orders.)
Perhaps you would like just to glance at such pamphlets as I can lay my
hands on, and therefore I will send them, as if you do not care to see
them you can return them at once; and this will cause you less trouble
than writing to say you do not care to see them. With respect to
Primula, and one point about which I feel positive is that the Bardfield
and common oxlips are fundamentally distinct plants, and that the
common oxlip is a sterile hybrid. (694/4. For a general account of
the Bardfield oxlip (Primula elatior) see Miller Christy, "Linn. Soc.
Journ." Volume XXXIII., page 172, 1897.) I have never heard of the
common oxlip being found in great abundance anywhere, and some amount
of difference in number might depend on so small a circumstance as the
presence of some moth which habitually sucked the primrose and cowslip.
To return to the subject of crossing: I am experimenting on a very large
scale on the difference in power and growth between plants raised from
self-fertilised and crossed seeds, and it is no exaggeration to say that
the difference in growth and vigour is sometimes truly wonderful. Lyell,
Huxley, and Hooker have seen some of my plants, and been astonished; and
I should much like to show them to you. I always supposed until lately
that no evil effects would be visible until after several generations
of self-fertilisation, but now I see that one generation sometimes
suffices, and the existence of dimorphic plants and all the wonderful
contrivances of orchids are quite intelligible to me.

LETTER 695. TO T.H. FARRER (Lord Farrer). Down, June 5th, 1868.

I must write a line to cry peccavi. I have seen the action in Ophrys
exactly as you describe,