32 



COLLEGE BOTANY 



three very definite forms ; (a) the unbranched, which is charac- 

 teristic of the palms and corn; (b) the deliquescent type (Fig. 

 10), in which the primary stem subdivides into two or more 

 branches, which in turn subdivide into numerous 

 branches, as in the elm and oak; (<?) the excur- 

 rent type (Fig. 11), in which numerous side 

 branches are borne on a single primary stem, 

 as in the pines. (2) The acaulescent type (Figs. 

 12 and 13), in which the internodes are very 

 short, bringing the leaves into a close mass or 

 rosette, as in the dandelion, turnip, radish and 

 beet (3) The fleshy type, which is made up 

 largely of parenchyma tissue, such as the cactus. 

 This type of stem serves for storage of water and 

 food. (4) The culm or grass type (Fig. 14), 

 which may be solid or hollow and is character- 

 istic of the grasses and grains. (5) The 

 climbing type (Figs. 32 and 33), which must 

 cling to other objects for support, such as the 

 morning-glory and many beans. The tendrils of 

 cucumbers, pumpkins and grape vines are stems 

 which are specialized for climbing by coiling 

 around a support. The tendrils of the Virginia 

 creeper are branched and have disk-like growths 



b 



FIG. 9. stem with on the tips for attachment to walls. (6) The 



buds arr a nged 



.opposite. decumbent type, which starts erect and curves 



towards the ground at the tips, as in the blackberries and 

 raspberries. (7) The prostrate or creeping type (Figs. 15 

 and 16), which lies on the ground, as in the ivy, strawberry, 

 melons and creeping clover. (8) The rhizome or rootstock 



