350 BOTANY [Chap. XI 



Letter 674 layer, which I find is sufficient to cause them to be devoured 

 by birds. 



I have received your paper on Martha \Posoqneria *] ; it 

 is as wonderful as the most wonderful orchis ; Ernst Hackel 

 brought me the paper and stayed a day with me. I have 

 seldom seen a more pleasant, cordial, and frank man. He 

 is now in Madeira, where he is going to work chiefly on 

 the Medusae. His great work is now published, and I have 

 a copy ; but the german is so difficult I can make out but 

 little of it, and 1 fear it is too large a work to be translated. 

 Your fact about the number of seeds in the capsule of the 

 Maxillaria' 2, came just at the right time, as I wished to give 

 one or two such facts. Does this orchid produce many 

 capsules ? I cannot answer your question about the aerial 

 roots of Catasetum. I hope you have received the new 

 edition of the Origin. Your paper on climbing plants 3 is 

 printed, and I expect in a day or two to receive the spare 

 copies, and I will send off three copies as before stated, and 

 will retain some in case you should wish me to send them 

 to any one in Europe, and will transmit the remainder to 

 yourself. 



Letter 675 To F. Miiller. 



Down [received Feb. 24th, 1867]. 



Your letter of Nov. 2nd contained an extraordinary 

 amount of interesting matter. What a number of dimorphic 

 plants South Brazil produces : you observed in one day as 

 many or more dimorphic genera than all the botanists in 

 Europe have ever observed. When my present book is 

 finished I shall write a final paper upon these plants, so that 

 I am extremely glad to hear of your observations and to see 

 the dried flowers ; nevertheless, I should regret much if I 

 prevented you from publishing on the subject. Plumbago^ 

 is quite new to me, though I had suspected it. It is curious 

 how dimorphism prevails by groups throughout the world, 

 showing, as I suppose, that it is an ancient character ; thus 



1 Bot. Zeitung, 1866. 



2 See Animals and Plants, Ed. II., Vol. II., p. 115. 



3 Linn. Soc. Journal, IX., 1867, p. 344. 



4 Plumbago has not been shown to be dimorphic. 



