18 



BULLIFORM CELLS. 



bt'CMi called Injyrosatjdc 

 (iells. They iiro usually 

 more or less wedge-sliap- 

 ed, with the jjoiiit of the 

 wedge towards \\w out- 

 side of thelea^ In Zea 

 mayx (Indian (^orn) 

 these cells are raised 



Fio. 20.— This illustrates the cross section at the . , , 



margin of a leaf of ^mp/jicarjJK/ii i^irWiif, shown in al)OVe the other cells 

 three i)laces, at a, there is a growth of peculiar ccIIm 



8urroun(iin«the basoof ahair,at/(, wehavoanotlier jiiiil imflF out. lilcp n 

 view, and ate, where no hair is seen, the larKCKrou;)"'^ l'^*- ""'' ^^'^^ '^ 

 of hypodermal fibers is covered by an ordinary epi- t,i' j.„„ 

 dermis. 1 x40.-(Suaworth.) UllStei. 



AVheii viewed on the surface of 

 tlie leaf, the hulliforni cells are 

 usually seen to have the propor- 

 tions of length and width much 

 like those next to them. In some 



Fio21.— A portion of a cross-section ,■, ,. , ., 



of a leaf of Zea ma\i», siiowintf one cases these cells are as long as wide, 



band of bulliform cells raised above 



the surface. 1 « i7.-(Sudwortii.) ^yjth outlines somewluit Avavy. 



The number of rows in a species is always the same, but varies 

 with the species from 3 to 12 in a band. If there are many rows, 

 the cells are shallow; if few rows, the cells are deep; if three 

 only, those at the side are small, and the middle one is very large. 

 The arrangement of these cells is invariable in a species, but in 

 a genus they vary much. The following examples are given : 



Fia. 22.— Cross-section of a leaf of Cynodon Dnctulon, showing a very large bulliform. 

 cell, with one or two small ones on each side of it. 1 x 130.— (Sudworth). 



