BARBER-FRUITS AND SEEDS OF CUCURBITACEAE 2 7 7 



goal!, polygonal, somewhat elongated cells, about 25^ in diameter, 

 with numerous minute pits, giving the walls a beaded appearance. 

 This layer, without intercellular spaces, is three to five cells thick, 

 the number increasing toward the edge of the seed. 



3. Sclerenchyma (scl) .-Firmness is given to the spermoderm by 



one laver (over the edge two or three) of longitudinally elongated 



250 p) cells, arranged end to end in rows. In surface view, both side 



and end walls are sinuous, often reaching 20 n in thickness. Alter 



maceration 



maceration ana uy carciui iulumh^, ui^. w~^ -- — 



these cells may be seen to send out remarkable ramifications, whose 

 dichotomous branches overlap one another. In transverse section 

 the oval appearance of the cell cavity is a characteristic feature, 

 few pits may be seen with a high power. 



4. Parenchyma.-Theie are three quite distinct layers, the paren- 

 chyma showing the greatest differentiation in this species. In cent 

 with the sclerenchyma is the first layer of small pitted cells, wit 

 or no intercellular spaces (m 1 )- Resting on this compact lay , 

 either singly or in groups, are larger cells, which stand out 11 

 branches in the intercellular spaces of the next layer. 



The cells of the second layer are characteristic of the genu. ^ 

 In this species the layer is two cells thick, with intercellular spaces 

 large that they form a great cavity in which the cells are ■»*» ' 

 In form the cells are somewhat stellate, joining the P"*"* *. 

 by one branch or a similar but smaller cell. The walls are beam £ 

 reticulate, the thickenings following a definite course aio ^^ 

 curved surface of the cell. The cross walls are netted in 



' iat lar § er mesh ' u , nt livers 



.chvma consists of a number ot la 



somew 



of 



pongy 



the tissues 



may 



Javelle waiei ~r— 

 The cells are thin- 



'- * (f,P 2V In 



"*uea, decreasing m size toward the innei ^— 'enter of the 

 surface view the contour of the branches appears, m "f color b 

 ce "V as rings nearly as large as the cells themselves. A » 

 £ v en to these inner layers by chlorophyll. t hin-walled 



5- The inner epidermis (p*) is composed of sma , 

 cells, 



P«.sper u (fys. 5 , 6, N).-In this coat there are about * Uycr- 



