32 



SUBTERRANEAN SHOOTS 



corm, so that when the mother-corm shrivels up, the several new 

 corms become separate and form distinct individuals. The 

 adventitioiis roots are given off jfrom the old corm, and serve 

 to supply water and nutriment to the flowering axis and to the 

 developing corm. 



A bulb is a subterranean shoot which consists of a short bun- 

 like stem with fleshy scales. The main mass of the bulb is 

 made up of leaf-structures. In the case of the bulb of the 



Tulip the scales are 

 complete scale-leaves, 

 and the plant has 

 foliage-leaves in addi- 

 tion. But the scales 

 of some bulbs are not 

 complete leaves, they 

 are merely the persis- 

 tent basal portions of 

 green leaves, the 

 blades of which have 

 decayed- For in- 

 stance, the single stem 

 of a Snowdrop, which 

 terminates in an in- 

 florescence, bears two 

 long, narrow foliage- 

 leaves, which are 

 attached to its base. 

 As the season ad- 

 vances, the green 

 upper portions of 

 these two leaves decay 

 and their bases thicken 

 to form two fleshy 

 scales. The bulb of a 

 Snowdrop consequently consists mainly of two thick scales borne 

 on a short axis. In the axil of one of the scales is a bud which, 

 in the following year, will develop to form a new flowering 

 axis. As the latter grows, the two scales will shrivel as they 

 pass their contents on to the growing stem. This new flower- 

 ing shoot will subsequently behave just like its predecessor, 

 and the brown shrivelled remains of the two old scales will be 



Fig. S3. — Vertical section of bulb of Hyacinth 

 jr is the flattened axis ; 7? is the inflorescence axis 

 a is an additional lateral bud forming a small bulb. 



