422 BOTANY [CHAP. XI 



Letter 752 is the Agricultural Gazette : I have occasionally suggested 

 articles for publication to the editor (though personally un- 

 known to me) which he has always accepted. 



Permit me again to thank you for the thorough manner 

 in which you have worked out this case ; to kill an error is 

 as good a service as, and sometimes even better than, the 

 establishing a new truth or fact. 



Letter 753 To A. Stephen Wilson. 



Down, Feb. I3th, 1880. 



It was very kind of you to send me the two numbers of 

 the Gardeners* Chronicle x with your two articles, which I have 

 read with much interest. You have quite convinced me, 

 whatever Mr. Asher may say to the contrary. I want to 

 ask you a question, on the bare chance of your being able 

 to answer it, but if you cannot, please do not take the 

 trouble to write. The lateral branches of the silver fir 

 often grow out into knobs through the action of a fungus, 

 jEcidium ; and from these knobs shoots grow 2 vertically 

 instead of horizontally, like all the other twigs on the same 

 branch. Now the roots of Cruciferae and probably other 

 plants are said to become knobbed through the action of 

 a fungus 3 : now, do these knobs give rise to rootlets ? and, if 

 so, do they grow in a new or abnormal direction ? 



Letter 754 To W. Thiselton-Dyer. 



Down, June l8th, 1879. 



The plants arrived last night in first-rate order, and it was 

 very very good of you to take so much trouble as to hunt 

 them up yourself. They seem exactly what I wanted, and 

 if I fail it will not be for want of perfect materials. But a 

 confounded painter (I beg his pardon) comes here to-night, 

 and for the next two days I shall be half dead with sitting to 

 him ; but after then I will begin to work at the plants and 

 see what I can do, and very curious I am about the results. 



I have to thank you for two very interesting letters. I am 



1 Gardeners' Chronicle, 1879, p. 652 ; 1880, pp. 108, 173. 



2 The well-known " Witches-Brooms," or " Hexen-Besen," produced 

 by the fungus AZcidium elatinuin. 



3 The parasite is probably Plasmodiophora : in this case no abnormal 

 rootlets have been observed, as far as we know. 



