24 HOPS. 



The two last-named workers distinguisji three typical 

 forms of glands i-^- 



1. Clubbed glands; 



2. Disc-shaped glandular scales, and 



3. Cup-shaped glandular scales (lupulin granules, hop 

 flour). 



The club and disc forms occur on young stems, on the 

 foliage leaves (especially on the under side), on the bracts 

 and bracteoles (outside more than inside) of the flower and 

 fruit cones, but never on the perigonium. The lupuHn 



(a) Magnified ^K (b) Magnified a^. „ '" (c) Magnified ij^. 



Fig. 14. — Lupulin granule. 



(a) Development of the granule. 



(6) Granule not quite fully developed. 



(c) Granule viewed from above. 



granules, however, are met with in large numbers on the 

 female perigonium, less extensively on the bracts, and are 

 probably altogether absent from the stems and foliage. The 

 glandular hairs are of multicellular structure, and are formed 

 by the repeated subdivision of the mother cells, each of 

 which is separated, at an early stage, into a crown cell and 

 base cell by a partition wall. 



In the club-shaped glands (Fig. 12) the crown cell sub- 

 divides in a direction parallel or tangential to the axis of 

 the head, thus developing a small tissue, but never a cellular 



