My dear Sir

It was very kind of you to send me the two numbers of the Gard. Chron. with your two articles, which I have read with much interest. You have quite convinced me, whatever M^r. Asher may say to the contrary.¹ 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 Æcidium; and from these knobs shoots grow vertically instead of horizontally like all the other twigs on the same branch.² Now the roots of Cruciferæ³ and probably other plants are said to become knobbed through the action of a fungus; now do these knobs give rise to rootlets and if so do they grow in a new or abnormal direction?

Believe me, my dear Sir | Yours sincerely | Charles Darwin