LES80X 7.] SPINES, TENDIULS, AND riTCJIF.IlS, 



51 



leaves is plainly shown, in many cases, by the gradual transition 

 between tliein antl the Hrst foliage ot" the shoot. The Common Liiuc 

 and the 8hell-bark Hickory are good instances 

 of the sort. But the best illustration is fur- 

 nished by the Low Sweet liuckeye of the 

 Southern States, which is often cultivated as 

 an ornamental shrub. From one and the same 

 growing bud we may often find all the grada- 

 tions which an^ shown in Fig. 77. 



l-i;3. LfllVl'S as Spines occur in several plants. 

 The most familiar instance is that of the Com- 

 mon Barberry, In almost any summer shoot, 

 most of the gradations may be seen between the 

 ordinary leaves, with sharp bristly teeth, and 

 leaves which arc reduced to a branching spine 

 or thorn, jis shown in Fig, 78. The fact that 

 the spines of the Barberry produce a leaf-bud 

 in their axil also proves them to be leaves. 



124. Leiives us Tendrils are to be seen in the 

 Pea and the Vetch (Fig. 20, 127), where the 

 upper part of each leaf becomes a tendril, which 



the plant uses to 



climb by ; and in 



one kind of Vetch 



such a tendril. 



125. Leaves as Pitchers, or hollow tubes, 



are familiar to us in the common Pitcher- 

 plant or Side-saddle Flower (Sarrae^nia. 

 Fig, 70) of our bogs. These pitcliers 

 are generally half-fuli of water, in whi«'h 

 flies and other insects are drowned, often 

 in such numbers jis to make a rich 

 manure for the plant, no doubt ; though 

 we can hardly imagine this to be the 

 design of the pitcher. Nor do we per- 

 ceive hen; any need of a contrivance 

 liold water, since the roots of these 

 plants are alwavs well supplied by the wet lH)gs wlure lluy grow. 



the whole leaf 



h'Ul. 78. t>iiiiiiiicr nIkniI III llarlxTry, Klinwing llir Ir.iiisiliini of Ir.tvpK iiit.> i<|iinrH. 

 Flli. 79. L^afuf Saxraraiiu |iurjiurua, entire, and aiiuUier with llio U|)|icr jtart cut off. 



