iv INTRODUCTION. 



§ 2. The Root. 



18. Roots ordinarily produce neither buds, leaves, nor flowers. Their brauchc?, 

 called y^S/T^ when slender and long, proceed irregularly from any part of their surface. 



19. Although roots proceed usually from the base of the stem or stocky they may 

 also be produced from the base of any bud, especially if the bud lie along the ground, 

 or is otherwise placed by nature or art in circumstances favourable for their deve- 

 lopment, or indeed occasionally from almost any part of the plant. They arc then 

 often distinguished as adventUioifs^ but this term is by some applied to all roots which 

 are not in prolongation of the original radicle. 



20. Roots are 



JihrouSy when they consist chiefly of slender fibres. 



tuberous^ w^hen cither the main root or its branches are thickened into one or 

 more short fleshy or woody masses called tubers (25). 



taproots^ w^hen the main root descends perpendicularly into the earth, emitting 



only very small fibrous branches. 



21. The stock of a herbaceous perennial, or the lower part of the stem of an annual 

 or perennial, or the lowest branches of a plant, are sometimes underground and assume 

 the appearance of a root. They then take the name of rldzome. The rhizome may 

 always be distinguished from the true root by the presence or production of one or 

 more buds, or leaves, or scales. 



3. The Stock. 



• 22. The Stock of a herbaceous perennial, in its most complete state, includes a 

 small portion of the summits of the previous year's roots, as "well as of the base of the 

 previous year's stems. Sucli stocks will increase yearly, so as at length to form dense 

 tufts. They will often preserve through the winter a few leaves, amongst which are 

 placed the buds which grow out into stems the following year, whilst the under side of 

 the stock emits new roots from or amongst the remains of the old ones. These peren- 

 nial stocks only diifer from the permanent base of an undershrub in the shortness of 

 the perennial part of the stems and in their texture usually less woody. 



23. In some perennials, however, the stock consists merely of a branch, w^hich pro- 

 ceeds in autumn from tlie base of the stem either aboveground or underground, and 

 produces one or more buds. This branch, or a portion of it, alone survives the winter. 

 In the following year its buds produce the new stem and roots, whilst the rest of the 

 plant, even the branch on which these buds were formed, has died away. These annual 

 stocks, called sometimes h^bernacula, offsets^ or stolons, keep up the communication 

 between the annual stem and root of one year and those of the following year, thus 

 forming altogether a perennial plant. 



21. The stock, whether annual or perennial, is often entirely underground or root- 

 like. This is the rootstock, to which some botanists limit the meaning of the term 

 rhizome. When the stock is entirely root-like, it is popularly called the crown of the root. 



25. The term tuber is applied to a short, thick, more or less succulent rootstock or 

 rhizome, as well as to a root of that shape (20), allliough some botanists propose to re- 

 strict its meaning to the one or to the other. An Orchis tuber, called by some a hioh, 

 is an annual tuberous rootstock with one bud at the top, A potato is an annual tu- 

 berous rootstock with several buds. 



26. A bulb is a stock of a shape approaching to globular, usually rather conical 

 above and flattened underneath, in which Uie bud or buds are concealed, or nearly so, 

 under scales. These scales are the more or less thickened bases of the decayed leaves 

 of the preceding year, or of the undeveloped leaves of the future year, or of both. 

 Eullj are annual or perennial, usually underground or close to the ground, but occa- 

 sionally buds in the axils of the upper leaves become transformed into bulbs. Bulbs 

 are said to be scalj/ when their scales are thick and loosely imbricated, tnnicated when 

 the scales are thinner, broader, and closely rolled round each other in concentric layers. 



27. A corm is a tuberous rootstock, usually annual, shaped like a bulb, but in wliich 

 the bud or buds are not covered by scales, or of which the scales are very thin and 

 membranous. 



