DICOTYLEDONS. 



171 



forms may be seen from the simple, external scales, through 

 immediate forms, to the complete foliage leaf. The veins of 

 the leaves are almost always much-branched, the veins either 

 being given off from one main vein or midrib (feather-veined 

 or pinnate-veined), as in an apple leaf, or there may be a 

 number of large veins radiating from the base of the leaf, as 

 in the scarlet geranium or mallow. Such leaves are said to 

 be palmately veined. 



Some of them are small her- 

 baceous plants, either upright 

 or prostrate upon the ground, 

 over which they may creep 

 extensively, becoming rooted 

 at intervals, as in the white 

 clover, or sending out special 



runners, as is seen in the 



strawberry. Others are woody 

 stemmed plants, persisting from 

 year to year, and often becom- 

 ing great trees that live for hun- 

 dreds of years. Still others are 

 climbing plants, either twining 

 their stems about the support, 

 like the morning-glory, hop, 

 honeysuckle, and many others, 

 or having special organs (ten- 

 drils) by which they fasten 

 themselves to the support. 



These tendrils originate in different ways. Sometimes, as in 

 the grape and Virginia creeper, they are reduced branches, either 

 coiling about the support, or producing little suckers at their 

 tips by which they cling to walls or the trunks of trees. 

 Other tendrils, as in the poison ivy and the true ivy, are short 

 roots that fasten themselves firmly in the crevices of bark or 

 stones. Still other tendrils, as those of the sweet-pea and 

 clematis, are parts of the leaf. 



FIG. 92. End of a branch of a 

 horsechestnut in winter, show- 

 ing the buds covered by the thick, 

 brown scale leaves, x l. 



