68 Principles of Plant Culture. 
B \, ' growth, scarcely ex- 
\ \) ceeded half an inch 
CS long. In Fig. 26, the 
\ parts that are increas- 
7; ing in length are con- 
EB e siderably shorter than 
a 2 the root-tips, (R. T.) to 
h which no sand adheres. . 
101. The Root- 
Hairs (Fig. 27 B.) de- 
velop just behind the 
elongating part of the 
rootlet, and are present 
_ in nearly all plants. 
*% Their object is to ab- 
sorb water, with the 
food materials it con- 
g, tains. The root-hairs 
ia greatly increase the ab- 
Me 
- & sorbing surface of the 
i? o . 
oF roots, just as leaves in- 
Ne 
§S crease the absorbing 
AR ‘Risurface of the plant 
+} above ground. Each 
% —root-hair consists of a 
Vareins'e elongated cell 
(Fig. 28), and in com- 
mon with the cells in 
other living parts of 
Fig. 26. Roots of young wheat plant. The parts the plant, is filled with 
inclosed in sand (R H ) are surrounded by root- protoplasm (13). As 
hairs. R. T. root-tips; e, older parts of root. Na- 2 
tural size. (After Frank and Tschirch) the extremity of the 
