17 



NOMENCLATURE OF THE STEM. 



1. Stems have already been mentioned as being of 

 six standard kinds , viz. trunks, stalks, straws, scapes, 

 fronds, and stipes. 



2. In the language of botany, stems are regarded ac- 

 cording to many particulars, but principally as concerns 

 their composition, direction, duration, substance, form, 

 mode of branching, and surface. 



3. Composition: If their composition is the subject 

 of remark, they are either called simple or divided. 



a. Simple when they consist of one piece only, without any 

 branches bearing leaves, as with the knotty-rooted fig-wort, bistort, 

 and date-plnm. 



b. Divided when they are divided into branches, as with most 

 plants. 



4. Direction: By the direction of stems is meant, 

 the manner or position in which they grow ; so that they 

 are sometimes said to be erect, at others, oblique, sup- 

 ported, climbing, decumbent, and procumbent. 



a. Erect when their position forms nearly a right angle with the 

 surface of a level soil. Erect stems, however, are of four kinds ; viz. 

 straight when they rise in an even perpendicular line, as in the sil- 

 ver-fir and spearmint; flexuous when they rise perpendicularly and 

 are regularly curved, as in the box-leaved staff-tree and common 

 birthwort ; tortuous when they are curved in different directions, 

 but not regularly, like the flexuous stems ; nodding when they have, 

 a bend at their summit, as in the cedar and Solomon's seal. 



b. Oblique when between a perpendicular and an horizontal 

 plane. Oblique stems are either ascending, as in the common toad-flax 



