334 Highfield : The Structure of a Garlic Bulb. 



When the leaf dies the petiole becomes detached from the 

 tubular base, thus leaving the scar which is seen on one side 

 of the bulb in fig, i. 



It may be conjectured that if the first leaf were removed 

 before flowering takes place, no seed would be set, and if from 

 another plant the second leaf were removed, a new bulb would 

 not be formed. 



If a number of the older and more deeply rooted garlic 

 bulbs are dug up in February or March, before the shoots have 

 developed, it is not uncommon to find two bulbs apparently 

 of the same degree of maturity joined together by a si ght woody 

 attachment at the base, but otherwise quite separate (fig. 3), 

 The attachment indeed is so slight that it will generally have 

 disappeared entirely by the time the leaves are above ground, 

 and there will be nothing to show that these bulbs have been 

 produced vegetatively. 



The production of these twin bulb structures is understood 

 when we examine sections of certain mature bulbs, and find 

 that in some cases two shoots are enclosed in a single sheath. 

 The two shoots may be of different ages and degrees of maturity, 

 but since at the end of the season the new bulb is formed only 

 from the last leaf base of each shoot, it follows that when the 

 outer rings have fallen away, the twins may both be of about 

 the same size and age. 



The reconstruction of the shoot and the origin of the twin 

 bulb structures can easily be followed in the autumn, after 

 the leaves of the plant have entirely disappeared. At this 

 time the bulbs present a similar appearance to that shown in 

 fig. I, except that the shoot has not yet emerged from the 

 hollow leaf base ; it is indeed, only to be found very low down 

 in the bulb. 



Fig 4 shows a series of transverse sections taken from the 

 same bulb. The outer food ring of the bulb is not shown. 



1. shows {b) the sheath ring, which is seen to resemble the 

 tubular base of an ordinary leaf, and'(c) the first leaf arising 

 from the axil of the sheath. 



II. — The first appearance of the flower is seen in the form 

 of two V-shaped structures, which represent the upper portions 

 of the spathe. The flower arises from the axil of the first 

 leaf (c). 



III. — The two portions of the spathe become united at their 

 edges. A second leaf (cf appears which, from its position is 

 seen to have arisen like the first leaf from the axil of the sheath. 

 It is this leaf which gives rise to the second shoot axis. 



IV.— The flower is seen in section. A third leaf (e) is seen 

 arising from the axil of the first leaf (c). 



v.— The two shoots are now seen separated from each other 

 by their enclosing outer leaf bases. A fourth leaf {e') arises 



Naturalist, 



