GROWTH OF PLANTS INDEPENDENTLY OF SEEDS 63 



have withered. In the Snowdrop, the bulb consists of a short 

 stem portion, which bears two scaly leaves. These are the bases 

 of the two green foliage-leaves of the snowdrop plant. Many 

 bulbs have scale - leaves on the outside ; foliage - leaves within 

 these ; floral-leaves in the centre. All these sets of leaves are 

 borne by the short stem. The accompanying illustration is a 

 medium vertical section of a Narcissus bulb, showing the scale- 

 leaves (sc) on the outside, within these the foliage-leaves, and in 

 the centre the floral-leaves (/). 



Onions and Shallots are bulbs commonly grown in kitchen 

 gardens. Onion seed, sown 

 the end of February or 

 early in March, will produce 

 young onions for salad by 

 June. If wanted for the winter 

 they should be disturbed as 

 little as possible, though care 

 should be taken to keep the 

 ground free from weeds. When 

 the bulbs are fit to gather 

 they should be laid out on 

 an open piece of ground, 

 where they will dry and 

 harden ; they should be turned 

 two or three times a week, and when thoroughly dried stored for 

 the winter. 



Bulbils are small buds produced in the axils of foliage leaves, 

 as in the Lesser Celandine and some lilies. These bulbils contain 

 stores of reserve material, and dropping off the parent plant form 

 new plants. 



(iii.) By corms. The Crocus is an example of a plant which 

 propagates itself by a corm, a structure very closely allied to 

 a bulb and differing from it mainly in the relative porportion 

 of stem and leaves. The greater part of the corm consists of 

 the stem portion, whilst the scale leaves are few ; just the reverse 

 is the case in the bulb. It follows that in the Crocus the food 

 is contained in the stem ; in the bulb it is stored in the leaves. 

 In order to understand the life-history of the Crocus, corms 



FIG. 33. Median vertical section of Narcissus 

 bulb, sc, scale-leaves ; /, floral-leaves ; 

 , bud ; s, stem. 



