MICROSCOPIC STRUCTURE OF WEED SEEDS 



513 



Fig. 390. Broom-corn. Fruit with chaff, r, two staminate spikelets ; g 1 , lower 

 empty glume; g 2 , upper empty glume; g 3 , glume of rudimentary flower; gf, 

 flowering glume with awn ; p, palet ; c, caryopsis. X 4. 

 (After Win ton, Conn. Agr. Exp. Sta.) 



with granular contents. The hairs, which are almost invariably- 

 detached in preparing the mount, if not in cleaning the seed, are 

 often 1.0 mm. long and 0.012 mm. broad in the middle but taper 

 toward both ends. Invariably the lumen is much broader than 

 the walls. 2. The Hypoderm Fibers, of which there are several 

 layers, have thick walls and narrow cavities. They vary in length 



Fig. 391. Broom-corn. Transverse section of caryopsis and an empty glume. 

 Sp, empty glume, consisting of the outer epidermis aep, the fiber layer f, 

 the spongy parenchyma p, and the inner epidermis iep ; g, bundle ; sto, 

 stoma ; Fs, pericarp, consisting of the epidermis ep with the cuticle c, the 

 hypoderm hy, the starchy mesocarp mes, the cross-cells q, and the tube-cells 

 sch ; N, nucellar or hyaline layer with swollen inner walls s ; E, endosperm, 

 consisting of the aleurone layer al and the starch-cells with starch 

 granules st and proteid network a. X 160. 



(After Winton, Conn. Agr. Exp. Sta.) 

 33 



