Commercial Gardening 



Small ones are produced at the base of the Gladiolus corm and serve for 

 propagation. 



A tuber is a short, not flattened, but fleshy stem, growing a little at 

 the apex and dying a little at the base every year. Roots are given off 

 from the sides, as in the Arum Lily and Caladium. The tuber of the 

 Potato is the thickened and fleshy end of an underground branch, which 

 develops into a new plant, the stem of which bears the roots, while the 

 old tuber dies. The Potato stores starch, while the tuber of the Jerusalem 

 Artichoke stores inulin, and both are cultivated for these reasons, being 

 useful for food. The tuber of the Jerusalem Artichoke is of similar origin 

 or structure to that of the Potato. 



Rhizomes are creeping, underground stems, giving off roots below and 

 leaves and flower stems at the end of the main axis or side branches. 



Fig. 26. Rhizome of Iris 



Fig. 27. Rhizome of Sedge (Carex) 



Examples of stout rhizomes are those of Solomon's Seal and many of the 

 Irises (fig. 26). Slender rhizomes are produced by Couch Grass, Sedges 

 (fig. 27), Lily of the Valley, and many others. The stem nature of these 

 rhizomes may often be testified by the presence of very much reduced 

 scale-like leaves, as in the cultivated Spearmint and Peppermint. 



The object of bulbs, corms, and tubers is to store food with which 

 to commence growth, flower, and fruit in the following year. Rhizomes 

 serve a similar purpose as well as to increase the plant and extend it 

 into fresh ground. Mints are noteworthy in this respect. All of these 

 types are of easy propagation by offsets and divisions in gardens. By 

 virtue of the stored food in their bulbs Hyacinths, Tulips, Daffodils, 

 Snowdrops, and others may be grown in the dark till their flowers are 

 visible, when they must be placed in the light for the benefit of the 

 young leaves. The Hyacinths and Daffodils may be, and are, grown 

 entirely in clean water till they have finished flowering, solely as a result 

 of the starch stored in the leaves and fleshy stems constituting the bulbs. 

 They require to be grown in good soil for some years afterwards in order 

 to recuperate before they can flower as well again. 



Besides such modified stem structures as corms, tubers, and rhizomes 



