STEMS AND STALKS. 



59 



organs and not their internal structure ; or* in other words, it is 

 the anatomy and not the physiology of plants, which we are now 

 attempting to explain. 



The different kinds of stems, or stalks, have been divided in- 

 to seven classes, as follows 



Caulis* or proper stem, Culm, Scape, Peduncle, Petiole, 

 Frond and Stipe. 

 Fig. 20. 



1st. Caulis or proper stem, is such as is seen 

 in forest trees, in shrubs, and in most annual 

 plants. The caulis is either simple, as in the 

 , white lily ; or branching as in the geranium ; 

 the branching is the more common form. You 

 vhave here Fig. 20, the representation of a 

 * caulis, or proper stem, (a) ; a peduncle, or flow- 

 er stalk, (b); and the petiole, or leafstalk, (c). 



Fig. 21. 



2d. Culm, or straw, (Fig. 21 ) is the kind of 

 stem which you see in grasses and rushes. The 

 culm is either without knots, as in the bulrush, 

 jointed or knotted, as in wheat and indian corn, 

 geniculated or bent like an elbow, as in some of 

 the grasses ; those culms which are bent, are also 

 knotted, though they may be knotted without be- 

 ing bent. The Bamboo, Sugar Cane, and vari- 

 ous species of Reeds have stems of the culm kind'; 

 some of them, particularly the Bamboo, are 

 known to attain the height of forty feet. 



* This kind of stem is by the French called tige; the i should be sounded 

 like e, the g soft likej, as teje. The word Caulis is from the Greek Kaulos, a 

 stem. 



Division of stems Caulis Culm. 



