Hippeastrum. In spite of
the uniformness of the results obtained in many successive years, Darwin
inferred that the plants must have been in an "unnatural state.") I am
not sure that I understand your result, [nor] whether it means what I
have above obscurely expressed. If you can prove the above, do publish;
but if you will not publish I earnestly beg you to let me have the facts
in detail; but you ought to publish, for I may not use the facts for
years. I have been much interested by what you say on the rostellum
exciting pollen to protrude tubes; but are you sure that the rostellum
does excite them? Would not tubes protrude if placed on parts of column
or base of petals, etc., near to the stigma? Please look at the
"Cottage Gardener" (or "Journal of Horticulture") (639/3. "Journal of
Horticulture" and "Cottage Gardener," March 31st, 1863. A short note
describing Cruger's discovery of self-fertilisation in Cattleya,
Epidendrum, etc., and referring to the work of "an excellent observer,
Mr. J. Scott." Darwin adds that he is convinced that he has underrated
the power of tropical orchids occasionally to produce seeds without the
aid of insects.) to be published to-morrow week for letter of mine, in
which I venture to quote you, and in which you will see a curious fact
about unopened orchid flowers setting seed in West Indies. Dr. Cruger
attributes protrusion of tubes to ants carrying stigmatic secretion to
pollen (639/4. In Cruger's paper ("Linn. Soc. Journ." VIII., 1865; read
March 3rd 1864) he speaks of the pollen-masses in situ being acted on by
the stigmatic secretion, but no mention is made of the agency of ants.
He describes the pollen-tubes descending "from the [pollen] masses still
in situ down into the ovarian canal."); but this is mere hypothesis.
Remember, pollen-tubes protrude within anther in Neottia nidus-avis. I
did think it possible or probable that perfect fertilisation might have
been effected through rostellum. What a curious case your Gongora must
be: could you spare me one of the largest capsules? I want to estimate
the number of seed, and try my hand if I can make them grow. This,
however, is a foolish attempt, for Dr. Hooker, who was here a day or two
ago, says they cannot at Calcutta, and yet imported species have seeded
and have naturally spread on to the adjoining trees! Dr. Cruger thinks I
am wrong about Catasetum: but I cannot understand his letter. He admits
there are three forms in two species