302 



BOTANICAL GAZETTE 



[\PRI1. 



the epicarp and outer mesocarp, the inner of the hard, stiff bundle- 

 with only vestiges of ground tissue. 



i. Epicarp (Jigs. 37, 39).— The cells of this layer are slightly 

 thickened, in surface view appearing polygonal and distinctly 

 beaded. On the spines the epidermal cells are elongated and have 



thick walls. 



The tip of each spine (figs. 35, 36) curves decidedly, bearing at 

 the very extremity, or more frequently just below it, a long, jointed, 

 capitate hair. There is great variation among these hairs. They 

 point downward, upward, or in an intermediate direction; the joint 

 may be few or many, the length of the hair varying accordingly. 

 Each cell is about as long as broad, with moderately thickened outer 

 and slightly thinner cross walls. The head consists of one cell 



(fig- 35) . two ( fig 



(fig 



about a common axis. They have 

 free rounded ends and are elongated, 

 with longitudinal diameter twice tha 



of the transverse. 



Similar hairs, but much shorter, 

 with one- to three-celled stalks, arc 

 present on the sides of the spa* 



Fig. 39 .-Echinocystis lobata Torr. (fig. 38) . All of the hairs frequent! 

 &Gr. Pericarp in surface view; epicarp disappear before the trUlt 

 with hy, hypoderm. X 160. . .. . 



maturity. . ^ 



Interspersed among the spines are the stomata with sma P> 



accompanying cells. 



2. Hypoderm (fig. 30, hy 

 this layer. They are polygonal, thick-walled, ana «*" - ^ 

 intercellular spaces at the angles, about which the wa * ^ ^ 



thick. In the spines the walls are also thickened and pittec . 

 r . . „ ohw, v,vnoderm *n°*- 



-Several layers of pitted cells make up 



onal. thick-walled, and have c,rc* 



inally. The *H«-*£ 



addition very much elongated longitudinally, itie n>p ^ 



through the transparent epicarp, the circular intercellular spac^^_^ 

 strongly thickened surrounding Walls, being especially cha ™ enchvma 

 3. Outer mesocarp.— Several layers of isodiametric V aT ^^ gn( ] 

 cells form the tissue below the hypoderm. The cells are - 



. 1 | - — 



thin-walled. 



