82 



Woodhead : Notes on the Bluebell, 



with cultivated ones the change seems to be brought about as 

 follows. One by one the long" outer scale leaves die (Plate V. , 

 Fig-. 7, Specimens 2, 4, and 7), the inner young-er ones are 

 shorter and thicker towards the base. Thus gradually the bulb 

 becomes more uniform in thickness, though for some time the 

 upper part exceeds the base in diameter. 



At this period (July) bulbs are commonly supposed to be 

 'resting,' but such is not really the case. The bulb scales 

 contain a store of reserve material, which, as shown by Parkin,"*^ 

 is inulin, starch occurring only in minute quantities towards the 

 apex of the axis. Within the bulb changes are going on, in 

 preparation for the renewed growth of roots so evident at the 

 end of July and during August. 



This activity continues throughout September, when the new 

 bud for the following spring enlarges considerably, and by the 

 middle of December may have sent up leaves three or four 

 inches out of the bulb. 



These are now seen to be surrounded b}" two specially 

 modified scale leaves which are thin, colourless, and tubular. 

 They closely ensheathe the foliage leaves in such a way as to 

 form a smooth outer covering which keeps the leaves compact^ 

 and so enables them to push their way through the soil without 

 injury (Fig. 7, b tu.l). On nearing the surface in January the green 

 leaves elongate more rapidly, push their way through the apex 

 of the inner sheath and gradually expand (Fig. 7, c). The 

 outer sheath by this time extends some two inches above the 

 bulb, the inner one being about two inches longer. In the 

 younger bulbs only one sheathing leaf is formed. Fig. 7, e, 

 shows a section of the sheath surrounding a single leaf, and 

 there is still but one sheath even in bulbs with four or five foliage 

 leaves. Outside these are four or five true scales, tr. s. 



Vertical sections of bulbs at this period show interesting" 

 phases of adventitious root development. These arise from the 

 solid stem in considerable numbers and have to make their wax- 

 through the fleshy scale leaves. Fig. 7, a, shows a section of 

 such a bulb with numerous roots boring through the scales. 

 Fig. 7, d, shows the tip of one of these, surrounded by the large 

 cells of the scale. The cells immediately around the tip are 



■ Parkin, Depletion of Carboh\"drates in Monbcot} ledon.s, Phil. Trans. 

 B., 1899, p. 35. See also Keeg-an, Chemistry of some Common Plants, 

 Naturalist, I903, p. 229. 



NOTK. — The reserve materials in the seed consist larg-el}- of proteid 

 granules, not starch. 



N;iU;r.,l:s 



