HAIRS ON THE LEAF. 



17 



with Ji root-hair. They iisually point to tlie apex of a leai or 

 stem, but in Lirrxia (rice cut- grass), they ])oint downward, 

 and become stout supporting hooks. 



Tragus racemo- 

 sus,At)ij)hicarpuvi 

 Purshii, Pani' 

 cum c (12) Hi (I re 

 (hair grass) and 

 others, have stout 

 hairs on the mar- 

 gins of the leaf. 

 On some smooth 



looTna +lir> l^oi'i.c FiG. 10.— Part of iv cross RBCtion of 3fe?fca «<ric(a, showiii« 

 iea\es, tne nans, many r.tiff hairs. lx;u.-(Sud\vorth.) 



when young, drop off and leave scars which alternate with the 

 larger cells of the epidermis. 



Bulliform Cells. — We will now consider more in detail tlie 

 bands of bulliform (blister) cells M-hich are larger than other 

 cells of the epidermis, and have thinner w-.uu^. Tliey have also 



