CAPE OKCHIDS AND OXALTS : 1863 223 



admirable powers of observation. I did not know all 

 this ; otherwise I sh d not have thought of asking for 

 plants. Think not a moment more on subject. Indeed 

 I ought to work on other subjects. Yet I am going to 

 ask a favour, if you know any one who dabbles in 

 Botany, viz., for seed of any Cape Oxalis : several species 

 present two forms, one with long pistil and short 

 stamens; the other form with short pistil and longer 

 stamens. It is of high interest to me to get seed of any 

 such species. To return to Orchids, I now believe that 

 Hymenoptera and Diptera are generally the chief 

 workers more than Lepidoptera. With respect to the 

 limits of Rostellum ; it can in most cases be told only 

 conjee turally : in Disa the 2 discs (and no part of caudicle 

 of pollinia) and the part which connects the 2 discs 

 with the medial upward central fold or ridge, and whole 

 face of column down to the two confluent stigmas, may 

 all be considered as the rostellum or modified third 

 stigma. With sincere thanks and every good wish, 

 Believe me, my dear Sir 



Yours sincerely 



C. DARWIN 



August 27th[, 1863] DOWN. 



BROMLEY. 



KENT. S.E. 

 MY DEAR SIR 



I am very much obliged for your very pleasant 

 letter. You have hit upon the right case in Oxalis, 

 and seeds will really be a treasure to me. I have posted 

 a paper for "you on the dimorphism of Linum which 

 if you will read, you will see why I am anxious for 

 Oxalis I have a more curious case unpublished ; but the 

 whole class of facts strike me as very surprising. You 



