The Root-Structure of Dioscorea 
prehensilis. 
BY 
T. G. HILL, A.R.C.S., F.L.S., 
Demonstrator in Biology at St. Mary's Hospital Medical School , London . 
AND 
Mrs. W. G. FREEMAN, A.R.C.S. 
With Plate XIX, and a Figure in the Text. 
HE publication of a paper by Dr. D. H. Scott 1 placed 
1- botanists in possession of two new examples of spine- 
bearing roots. Of the plants considered one, Dioscorea prehen- 
silis , Benth., forms the subject of the present communication. 
The plant described by Dr. D. H. Scott was grown at Kew, 
and the tuber was entirely a subterranean organ. It appears, 
however, that in the natural state the tuberous stem is almost 
entirely an aerial structure, a fact which is very clearly 
demonstrated by a photograph of the wild plant, taken by 
Mr. G. F. Scott-Elliot. The following interesting remarks 
are quoted from a letter from Mr. G. F. Scott-Elliot to 
Dr. Scott, which the writer has kindly allowed us to make 
use of. ‘The plant was, I should say, 7 feet high and 
completely covered by the arched roots. ... It was photo- 
graphed and collected in a day’s march, and there is not, 
I think, very much Natural History to be found from such 
hurried observations. I have an impression that this country 
has many wild boar who are possibly the enemy. It is not, 
1 Scott, D. H. : On two new instances of Spinous Roots, Annals of Botany, 
vol. xi, 1897. 
[Annals of Botany, Vol. XVII. No. LXVI. March, 1903.] 
