220 SIR JOHN LUBBOCK ON 
point develops into a simple tendril on the middle and upper 
portions of the stem. The tendrils represent the leaves, and are 
alternate and distichous ; that is, on the 3 plan of arrangement. 
The stipules are arranged in two ranks, inserted on the 
stem at right angles to the tendrils. They increase in size 
as the plant gains in vigour, and become obliquely triangular- 
hastate, but continue flat in bud and afterwards. The venation 
consists of numerous, parallel nerves, radiating from the point of 
insertion on the stem, the midrib being slightly the strongest. 
Succeeding pairs of stipules overlap and protect all the younger 
members of the terminal and axillary leaf- and flower-buds, and 
tendrils. All lateral buds come in the axils of the tendrils. The 
stipules, therefore, perform the double function of leaves and 
the work of protection. 
Rosace®. 
Pyrus Aria, Linn.—The scales of the winter-bud (Pl. 13. fig. 5. 
and figs. 25-35) of the White Beam-tree consist of the base of the 
leaf, that is the petiole in combination with the stipules. At the 
base of the winter-bud the persistent base of one or two leaves that 
fell in autumn may be found sheltering, it may be, axillary buds. 
The first scale (fig. 26) is semicircular and slightly erose at 
the apex, but otherwise entire. The second (fig. 27) is several 
times as large, and obtusely carinate. The third scale (fig. 28) 
shows three ribs or nerves, avd is about as long as the bud before 
growth is resumed in spring. The fourth is similar. The fifth 
scale (fig. 29) of a good-sized terminal bud (from which the 
sketches were made) was 3-ribbed, more membranous, greenish 
and trifid at the apex, thus disclosing the true nature of the 
scales, namely, a combination of the base of the petiole and the 
stipules. All the scales are rather firmly glued together by 
means of a viscid gum secreted from a cluster of orange-coloure 
glands situated close to the base on the inuer face. The sixth 
is similar. 
The seventh scale (fig. 30) is still more membranous, mor 
faintly 3-nerved, enclosing a large portion of the bud, very U2 
equally trifid, and enclosing 2 of the bud. The eighth is tri- 
dentate, and shows a transition towards the true nature of its 
component parts. . 
The ninth scale (fig. 31) is oblong, much narrower, and trifid. 
The middle tooth is subulate-terete, subfleshy and red, bemg 
more like a petiole than in any previous scale. The three nerves 
are now closer together and directed into the petiole. The side 
