12 



SYSTEM A TIC POMOLOdY 



nodes at the ^rowinjz: eml. Donnanl ])ai'1s of plants are not 

 elevated al)()ve the •rroimd hy «!:r()wtli, — a hrandi si)iiii«rinf^ from 

 the liMink of a tree at any distaiic*' from the Liroiiiid rdaiiis the 

 saiiic lit'iLdit tlirou^lioiil the life of the plant. 



20. Texture of stems. — Soft sueeuleiit si cms arc Jurhdcrous 

 and usually last l»ut one season. Stems which (h'vclo|> within 

 tliemselves considerable cpiantities of hard liber are woody. All 

 l)oin()lof!:ieal phmts of teni[)erate regions, ex- 

 eej)tin«^ the strawberry, are woody; the straw- 

 berry is svmi-herhaccous. All stems are herba- 

 ceous when young, and all herbaceous stems 

 possess more or less woody fiber, so that the dif- 

 ference between herbaceous and woody stems 

 is only in the de^^ree of develo})nient of the 

 woody tissues within them. 



21. Kinds of stems in hardy fruis. — Plants 



with a well-develoi)ed central woody trunk, 



with the head elevated at maturity more than 



three or four times the height of man, are trees. 



Plants with no very distinct central trunk, with 



chief branches much the same in thickness 



springing from or close to the ground are 



shrubs. Shrubs are usually less than three or 



four times the height of man. The adjectives 



shrubby, meaning shrub-like, and arbarescent, 



Grape tree-like, are common in pomolog5^ 



vinifera with dia- Several species cultivated for their fruits 



rotu ndif'ol ia ' \\ith ^^® ^^^ Weak in stem to maintain an upright 



pith continuous, position. Some of these, as the dewberries, 



grow along the surface of the ground; such 



stems are prostrate. Others, as several species of grapes, have 



stems too WTak to stand erect and find support on upright objects 



over which they clamber; these are climbing or scandent plants; 



some climbers are called lianas. 



Still another modified stem has very long internodes and runs 

 over the ground forming adventitious roots at the nodes, as in 

 the strawberries; these stems, usually destitute of leaves, are 

 runners (Fig. 5). They vary much in the character of the 

 internodes. The runner cords in some strawberries are thick 



