THE ' LUPULIN '-GLANDS OF THE HOP 



339 



one cell thick, and each cell possesses a thick cuticle, dense 

 protoplasmic contents, and a well marked nucleus. Before the 

 hop has quite assumed its cone-like shape, the cells of the cup 

 begin to produce a secretion which collects within the substance 



of the upper cell-wall of each 

 cell, and gradually lifts up the 

 cuticle much as the skin is lifted 

 up by matter in a blister. 



As more and more of the 

 secretion is poured out by the 

 secretory cells the hollow space 

 of the cup becomes filled up with 

 it, and the cuticle which covers 

 the secretion as a fine thin skin 

 is bulged out above the margin 

 ^ ;: T 1- 1 J r u I. of the cup, as at Fig. r, I o6. The 



Fig. io6. — Lupuhn-gland of the hop , ^ . 



(magnified). Outline of the cells is seen upon 



1. On very young hops in 'burr' stage. . ^ 



2. Vertical section of i. the CUticle, 



3. Fully developed gland, j Secretory ' 



ceii.s; c cuticle. The wholc Structure arises from 



4. Vertical section of 3. s Secretory . . . , , 



cells ; c cuticle ; o cavity filled with resin the epidermis of the bracts, and 



and oily contents. . ,.,,,,. 



IS a form of multicellular hair. 

 On account of its power to secrete it is termed a gland or 

 glandular hair. The connection of each gland with the surface 

 of the bract is very small and delicate — only the width of one 

 or two cells — consequently they are readily broken off when 

 touched. 



By rough treatment on the hair-floor where the hops are dried, 

 and also by careless shovelling when on the ' cooling ' floor, the 

 hops often become broken, and a considerable loss of these 

 valuable glands takes place. For the nature of the secretion 

 contained in the glands, see p. 345. 



Varieties. — So far as names are concerned a very large number 

 of varieties of hops are grown in England. Many of them, how- 

 ever, exist only in name, the same variety passing under dif- 



