NOTES ON ROOT-HAIRS AND ROOT GROWTH. 
173 
occur, not unfrequently caused 
by friction, but these I have 
found to be of a different cha¬ 
racter to the knaur and have 
no tendency to produce adventi¬ 
tious buds. I do not venture to 
give an opinion on the cause or 
causes which form the knaur, 
so little is known on the subject, 
and it seems very desirable to 
obtain more information on this 
interesting peculiarity of vege¬ 
table growth. I should wish it 
to be well understood that the 
drawings were made from the 
stem and branches of the tree 
long after the tree had been cut 
down. It would have been 
much more satisfactory if I 
could have examined it in the 
living state. I cannot but here 
thank E. Vivian, Esq., for the 
kind assistance he has given 
me as regards the diseased 
Acacia I have described. 
B 
No. 4. 
XXVII.—Notes on Root-Hairs and Root Growth. 
By Maxwell T. Masters, M.D., F.R.S. 
[Bead at a Meeting of the Scientific Committee, 22nd April, 1879.] 
The hairs which are observed on the younger and finer roots 
seem hardly to have received the attention at the hands of 
cultivators that their importance demands. With a view of 
directing attention to them, and of inducing others with more 
convenience and leisure than fall to my own lot, to observe and 
experiment upon them, I lay before the Committee the following 
notes which, though of a fragmentary and incomplete character, 
:may yet be of some service. 
The appearance of these root-hairs is familiar enough to 
