NOTES ON ROOT-HAIRS AND ROOT GROWTH. 
183 
(7.) Road Sand.— Mustard, 14—15,5—6, and8—9 centimetres. 
Cress, 12—13, 4—5, and 7—8 centimetres. 
The radicles of the Mustard were quite straight, with a few 
horizontal branches. The root-hairs were cobwebby, and very 
abundant; less so in the case of the Cress. 
The subjoined diagrams will show in brief and approximately 
some of the chief results of the experiments in the case of the 
Mustard and of the Cress respectively. 
MUSTARD 
1 2 S 4- <5 6 7 
N 2 
