12 BULBS AND THEIR CULTIVATION. 



vious year in readiness for the new stems to draw upon 

 the next season. It naturally follows, therefore, that 

 if the leaves are removed from the bulbs before they have 

 turned quite yellow and withered, less reserve food is 

 stored up in the scales, and the embryo spike or flower 

 stem has, consequently, an insufficient supply to enable 

 it to develop fully. Let the leaves complete their work 

 of manufacturing all the raw food sent up by the roots into 

 elaborated or reserve food to be stored up in the scales, 

 and then good flowers may be expected the next year. 



What is a Corm ? A corm is in general outward ap- 

 pearance like a bulb; but if the bulb of, say, a hyacinth 

 and the corm of a crocus be cut through, the difference 

 will be seen at once. Instead of fleshy scales, we shall 

 find a solid substance with just a few faint ridges on the 

 outside. These ridges are the remains of the few thin 

 scales the corm produced in a younger stage of develop- 

 ment. The fleshy solid contents of the corm are reserve 

 food prepared in the same way as that described in the 

 case of bulbs. This reserve food is wholly utilised by the 

 young growth and flowers, and at the end of the season 

 the corm which contained it will be found shrivelled up, 

 and new corms formed to take its place. A bulb practi- 

 cally goes on increasing in size year by year, if properly 

 grown, but a corm exists for one season only, its place 

 being taken by younger ones partly formed out of the re- 

 serve food of its parent and new food elaborated by the 

 leaves. Examine the corm of a crocus, gladiolus, or 

 Tritonia (Montbretia) at the end of the season. 



What is a Tuber? A tuber is a swollen under- 

 ground stem, which may simply be an enlargement of a 

 portion of a root, as in the case of Tropaeolum tuberosum, 

 and of one season's duration only; or an individual growth 

 of perennial duration, as in the case of the Winter Aconite, 

 Gloxinia, and Tuberous-rooted Begonia. It has almost 

 invisible leaf -scales upon its outer surface, and a solid 



