1 68 



FLOWER-LAND. 



made up of the long cells, is called " prosenchyma"* 

 (Fig. 144). 



In some parts of stems, however, you find another 

 kind of tissue. In a pile or column of cells, one 

 on the top of the other, the divisions between 

 them sometimes gradually disappear, or partly 

 so, so that there is a free passage from end to 

 end of the whole column or set of cells, and so is 

 formed a long tube or " vessel." The sides or walls of 

 these vessels differ a good deal according to the way 

 in which the original cell divisions or walls have been 

 removed or altered. I will only tell you that the 



Fig. 145. Spiral vessels. Fig. 146. Pitted vessels. 



most common ones are known as ringed (annular)^, or 

 spiral, or pitted, or scalariform \ according to these 

 differences in their walls (Figs. 145, 146, 147). You 



* From the Greek "pros," to, and " encheo" to pour in. 

 f From the Latin " annuhis" a ring, a curled lock of hair. 

 J From the Latin " scalaris" (scala) of a ladder, and "forma," shape 

 or form. 



