II! 
Briefe. 
Among 300 seeds from a pod fertilized with the same plants pollen only 
86 seemed to be good, while at least Vio appeared to be so in the pods fertilized 
with pollen of a distinct plant of the species or of Ep. Schbgkii. 
Fertilization with own pollen, at least in 
Orchids, seems to have much analogy with 
illegitimate unions of dimorphic plants or Cros- 
sing of distinct species ; it would be interesting 
to compare the offspring of plants fertilized 
with own pollen with hybrids and the illegitimate 
offspring of dimorphic plants. 
May not the individual plants of several 
species which were found to be quite sterile 
with own pollen, have been the offspring of 
flowers fertilized with own pollen? 
Fig. 36. Epidendrum cinnabarinum. i befruchtet am 
21. Deceraber mit Pollen von Ep. Schomburgkü. 2 befruchtet 
am 20. December mit Pollen derselben Blüthen. Die beiden 
oberen Zeichnungen vom 29. Dec. 1866, die beiden unteren, 
Früchte, vom 31. Jan. 1867. Aus dem Nachlass. 
I enclose an other dimorphic Rubiacea, probably a Diodia (I have not yet 
examined the fruit, which offers the main distinction between this genus, Spermacoce 
and Borreria) ; there is a small, but as far as I have seen constant, difference in the 
size of the poUen-grains, those of the short-styled flowers being larger 
An Fritz Müller von Darwin. 
Down-Bromley Kent. April 22 (1867) 
received May 27. 
Your letter of March contained much interesting matter, but I have to 
say this of all your letters. I am particularly glad to hear that Oncidium flexuosum is 
endemic, for I always thought that the cases of self-sterility with Orchids in hot-houses 
might have been caused by their unnatural conditions. I am glad also to hear of the 
other anaiogous cases, all of which I will give briefly in my book that is now printing. 
The lessened number of good seeds in the self-fertiiized Epidendrons is to a certain 
extent a new case. You suggest the comparison of the growth of plants produced from 
self-fertilized and crossed seeds. I began this work last autumn and the resuit in some 
cases has been very striking, but only as far as I can yet judge with exotic plants which 
do not get freely crossed by insects in this country. In some of these cases it is really 
a wonderful physiological fact to see the difference of growth in the plants produced 
from self-fertilized and crossed seeds, both produced by the same parent-plant ; the pollen 
which has been used for the cross having been taken from a distinct plant that grew in 
the same flower-pot. — — Have you ever thought of publishing a work which might 
contain miscellaneous observations on all branches of natural history, with a short descrip- 
tion of the country and of any excursions which you might take. I feel certain that 
you might make a very vaiuable and interesting book, for every one of your letters is 
so füll of good observations 
