272 CORMS AND BULB3. 



SECTION IX. 



CORMS AND BULBS. 



This section forms a natural sequence to the previous one 

 dealing with rhizomes and roots. It contains but two official 

 representatives viz., colchicum corm and squill bulb. The 

 former is a contracted hypogaeic stem, ths latter is composed of 

 a number of fleshy, modified leaves, enclosing a comparatively 

 small axis. 



131) Colchicum Corms. 



Colchicum corms are obtained from Colchicum autumnale, L. 

 (N.O. Liliacese). 



The corm exhibits the following structure : 



(1) Epidermis, composed of a single layer of flattened cells 

 which in surface view are seen to be very irregular in outline 

 and arrangement ; they have brown, pitted, more or less wavy 

 walls. 



(2) Ground tissue, consisting of polygonal parenchymatous 

 cells^with distinct intercellular spaces and filled with starch. 

 Thejlatter occurs mostly in compound grains ; these usually 

 have three rarely four components, which, when separated, are 

 curved on one side and angular on the others; they have a 

 conspicuous stellate hilum ; the simple grains are rounded. 

 This_tissue is traversed by numerous bundles, each consisting 

 otj& group of vessels surrounded by a ring of soft bast. 



The diagnostic characters of powdered colchicum corm are: 

 (a) The starch grains. 

 (6) The abundant parenchyma, 

 (c) The absence of sclerenchyma and of crystals. 



