138 



STEMS 



imbricated scales surrounding a central bud or growing point. 

 The tunicated bulb, as that of the onion, is composed of a 

 great number of concentric fleshy scales. The solid bulb or 

 corm is a bulb in which the scales have coalesced to form a 

 solid structure, as in colchicum and gladiolus. The com- 



FIG. 79. Direction of Growth. 1, Erect (Lobelia inflatd); 2, ascending 



branches of Viburnum acerifolium; 3, decumbent (Veronica officinalis); 



4, procumbent, partridge berry (Mitchella repens); 5, repent, cinquefoil 

 (Potentilla pumila). 



pound bulb, as that of the garlic, is made up of a number of 

 small bulbs arranged upon a flat disc-like rhizome. 



Aerial Bulbs or Bulblets. Aerial bulbs occur as axillary 

 bulbs in the axils of the leaves of tiger lily. In onion the 

 flowers are often replaced "by apical bulbs. 



