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IV 



OUTLINES OF 



are then often distinguished as adventitious, and this term is by some applied to all 

 roots M'hich are not in prolongation of the original radicle, 



20. Roots are 



fibrous, when they consist chiefly of slender .fibres. 



tuherousy when either the main root or its branches are thickened into one or 

 more short fleshy or woody masses called ^wJers (25). 



taproots, when 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 tlie 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 pro- 

 duction 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. . Such 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 foUowing year, whilst the 

 under side of the stock emits new roots from or amongst the remains of the old ones. 

 These perennial stocks only differ from the permanent base of an undershrub in the 

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



23. In some ]>erennials, however, the stock consists merely of a branch, which 

 proceeds in autumn from the 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 hyhcrtmcula, 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. ^ v ; 



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

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

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

 the root. 



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

 ■ or rhizome, as well as to a root of that shape (20), although some botanists propose 



to restrict its meaning to the one or to the other. An Orchis tuber, called by some 

 a knob, is an annual tuberous rootstock with one bud at the top. A potato is an 

 annual tuberous rootstock ^-ith several buds. 



2G. A buU> is a stock of a shape approaching to globular, usually rather conical 

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

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

 loaves of the preceding year, or of the undeveloped leaves of the future year, or of 

 both. Bulbs are annual or perennial, usually underground or close to the ground, 

 but occasionally buds in the axils of the upper leaves become transformed into 

 bulbs. Bulbs are said to be scaly when their scales are thick and loosely imbricated, 

 tunicnted 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 

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

 thin and membranous. 



§ 4. The Stem, 



28. Steins are 



erect, when they ascend i^erpendicularly from the root or stock ; (ici(;gy or vir- 

 gate, when at the same time they are slender, stiff, and scarcely branched. 



sarmcatose, when the branches of a woody stem are long and weak although 

 scarcely climbing. . / ,,.. . 



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