OUTLINES OF BOTANY. XV 



stem and roots, whilst the rest of the plant, eyen the branch on which these 

 buds were formed, has died away. These annual stocks, called sometimes 

 hybernacula, offsets, or stolons, keep up the communication between the annual 

 stem and root of one year and those of the following year, thus forming alto- 

 gether a perennial plant. 



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

 rootlike. 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 root- 

 stock or rhizome, as well as to a root of that shape (20), although some bota- 

 nists 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 with several buds. 



26. A bulb 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 thickenened bases 

 of the decayed leaves 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, tunicated 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 the bud or buds are not covered by scales, or of which the scales are 

 very thin and membranous. 



§ 4. The Stem. 



28. Stems are 



erect, when they ascend perpendicularly from the root or stock ; twiggy 

 or virgate, when at the same time they are slender, stiff, and scarcely 

 branched. 



decumbent or ascending, when they spread horizontally, or nearly so, at 

 the base, and then turn upwards and become erect. 



procumbent, when they spread along the ground the whole or the greater 

 portion of their length ; diffuse^ when at the same time very much and rather 

 loosely branched. 



prostrate, when they lie still closer to the ground. 



creeping, when they emit roots at their nodes. This term is also frequently 

 applied to any rhizomes or roots which spread horizontally. 



tufted or ccespitose, when very short, close, and many together from tho 

 same stock. 



29. Weak climbing stems are said to twine, when they support themselves 

 by winding spirally round any object ; such stems are also called voluble. When 

 they simply climb without twining, they support themselves by their leaves, or 

 by special clasping organs called tendrils (169), or sometimes, like the Ivy, by 

 small root-like excrescences. 



30. Suckers are young plants formed at the end of creeping, underground 

 rootstocks. Scions, runners, and stolons, or stoles, are names given to young 

 plants formed at the end or at the nodes (31) of branches or stocks creeping 

 wholly or partially aboveground, or sometimes to the creeping stocks them- 

 selves. 



31. A node is a point of the stem or its branches at which one or more 

 leaves, branches, or leaf-buds (16) are given off, An internode is the portion 

 of the stem comprised between two nodes. 



32. Branches or leaves are 



