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Herbs, Trees, ^ plant the serial stem of which is herbaceous and dies 

 down to the ground annually is called a herb. There are 

 some plants the stem of which, although it, dies down 

 annually, is firm and more or less woody, e.g. Psoralea 

 corylifolia. They are also usually classed as herbs. Plants 

 of which the serial stems, or the greater part of them, per- 

 sist for more than one year and which are more or less woody* 

 are classed as shrubs and trees respectively. 



A shrub is distinguished from a tree by its smaller size 

 and by the fact that it usually has branches near the base. 



According to their size, shrubs andtrees are again usually 

 sub-divided into shrubs, large shrubs, small trees, medium- 

 sized trees, large and very large trees. 



An undershrub is a plant, of the aerial stem of which a 

 very small portion persists for more than one year. Such a 

 plant is also sometimes said to be suffruticose, or suffru- 

 tescent. 



Large herbs which in size and general appearance re- 

 semble true shrubs are usually described as shrubby, e.g. 

 Sesbania aculeata. 



Climbing plants are termed herbaceous if their aerial stems 

 are herbaceous and die down annually, and woody if the 

 stems persist for more than one year and are more or less 

 woody. 



Biennials, A plant, or part of a plant, which only lives for one year 



Perennials, is called an annual, one which lives for 2 years a biennial and 



one which lives for more than 2 years a perennial. Annual 



plants are always herbs, biennial plants are usually herbs, 



while a perennial plant may be a herb, shrub, or tree. 



The persistent basal portion of the stem of an undershrub 

 and the persistent base of an herbaceous perennial, lying at, 

 or just below, the ground surface, and usually including a 

 small portion of the bases of the aerial stems and the upper 

 thickened portion of the roots and from which new herbaceous 

 stems are annually produced, is called a stock, or sometimes, 

 also, a root-stock.\ 



Such root -stocks gradually increase in size and often 



* In a few cases stems which persist for more than one year are distinctly 

 herbaceous, e.g. those of the Banana. 



| A rhizome is also called a root-stock by some botanists. 



