HAIRS ON THE LEAF. 



17 



witli :i root-]i:iir. They usually point to the ii])ex of a leai or 

 stem, hut iu Lcersia (rice-eut grass), tliey point downward, 

 and become stout supporting liooks. 



Tragus raccmo- 

 s us, A mpli iru rp u in 

 Piirshii, Pa u i - 

 cum r a J) ill a re 

 (hair grass) and 

 others, have stout 

 hairs on the mar- 

 gins of the leaf. 

 On some smooth 



looirrkc. +V.r> l^ni,.c Fig. 19.— Part of a cross section of JfeZica sfricta, showing 

 leaves, Xne nairs, many stiff hairs. 1 X 34.-(Sudworth.) 



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

 larger cells of the epidermis. 



Blllliforni Cells. — We will now consider more in detail the 

 bands of bulliform (blister) cells which are larger than other 

 cells of the epidermis, and have thinner walls. They have also 



