i865 i88i] F. MULLER 361 



States has described a species, and seems to doubt whether Letter 684 

 it is heterostyled, for he thinks the difference in the length of 

 the pistil depends merely on its growth ! In my new book 

 I shall use all the information and specimens which you have 

 sent me with respect to the heterostyled plants, and your 

 published notices. 



One chapter will be devoted to cleistogamic species, and 

 I will just notice your new grass case. My son Francis 

 desires me to thank you much for your kindness with respect 

 to the plants which bury their seeds. 



I never fail to feel astonished, when I receive one of your 

 letters, at the number of new facts you are continually observ- 

 ing. With respect to the great supposed subterranean animal, 

 may not the belief have arisen from the natives having 

 seen large skeletons embedded in cliffs ? I remember finding 

 on the banks of the Parana a skeleton of a Mastodon, and the 

 Gauchos concluded that it was a burrowing animal like the 

 Bizcacha. 1 



To F. M tiller. Letter 68s 



Down, May I4th [1877]. 



I wrote to you a few days ago to thank you about Ponte- 

 deria, and now I am going to ask you to add one more to the 

 many kindnesses which you have done for me. I have made 

 many observations on the waxy secretion on leaves which 

 throw off water (e.g., cabbage, Tropceolum)> and I am now 

 going to continue my observations. Does any sensitive 

 species of Mimosa grow in your neighbourhood? If so, will 

 you observe whether the leaflets keep shut during long-con- 

 tinued warm rain. I find that the leaflets open if they are 

 continuously syringed with water at a temperature of about 

 19 C., but if the water is at a temperature of 33- -3 5 C., they 

 keep shut for more than two hours, and probably longer. If 

 the plant is continuously shaken so as to imitate wind the 



1 On the supposed existence in Patagonia of a gigantic land-sloth, 

 see Natural Science, XIII. , 1898, p. 288, where Ameghino's discovery 

 of the skin of Neomylodon listai was practically first made known, since 

 his privately published pamphlet was not generally seen. The animal 

 was afterwards identified with a Glossotheriuvi, closely allied to Owen's 

 G. Darwini, which has been named Glossotherium listai or Grypotherium 

 doniestcium. For a good account of the discoveries see Smith Woodward 

 in Natural Science, XV., 1899, p. 351, where the literature is given. 



