ELEMENTS OF STRUCTURAi, BOTANY. 



69 



maae up of a number of coats. 

 Strip oil" one or two, and observe 

 that whilst they are somewhat 

 fleshy where the onion is broadest 

 they gradually become thinner to- 

 wards the toj). The long green 

 tubes, which project from the top 

 of the Onion during its growth, are, 

 in fact, the piolongations of these 

 coats. But the tubes are the leaves 

 of the plant. The mass of our Onion, therefore, con- 

 sists of the jJcfilnj Jkikcx of the haves. But you will 

 observe that at the bottom there is a rather flat solid 

 part upon which these coats or leaves 

 are inserted, and which must consequent- 

 ly be a stem. Such a stem as this, with 

 its fleshy leaves, is called a bulb. If the 

 leaves form coats, as in the Onion, the 

 bulb is coated or timicatcd ; if they do 

 not, as in the lilies (Fig. 102), it is scaly. 



93. Tubers and bulbs, then, consist chiefly of masses 

 of nourishing matter ; but there is this difference, that, 

 in the latter, the nourishment is contained in the fleshy 

 leaves themselves, whilst, in the former, it forms a mass 

 more or less distinct from the buds. 



04. The thickened mass at the base of the stem of 

 our Indian Turnip (Fig. 78) is more like a tuber than a 

 bulb in its construction. It is called a conn, or solid 

 bulb. The Crocus and Gladiolus of the gardens are 

 other examples. 



9". In the axils of the leaves of the Tiger Lily are 

 produced small, black, ronndcd bodies, which, on exami- 

 nation, prove to be of bulbous structure. They arc, va. 



-g. ll.2 



