142 LEAVES AND BUDS. 



Whenever any of the branches are pruned away or broken off by 

 high winds or by the weight of snow, buds develop which would other- 

 wise have remained dormant, and in this way trees are able to rapidly 

 fill up gaps in their canopy of foliage. So also pollarded willows soon 

 form a crown of new shoots, and many of these arise from deep-seated 

 buds, or from adventitious ones. The latter are buds which develop out 

 of their normal order, or without any relation to the leaves. Adventi- 

 tious buds may be formed not only upon the stem, but also on roots or 

 leaves. Some Begonias are artificially propagated by placing sliced 

 leaves on damp soil ; buds appear on the wounded edges, strike root, 

 and develop into new plants. Adventitious buds may appear on the 

 roots of the Hawthorn, Dandelion, and other plants, and may give ripe 

 to leafy or even flowering shoots. For example, tHe roots of the Haw- 

 thorn, if chopped into small pieces and covered loosely with damp soil, 

 produce buds and ultimately new plants. Most people are familiar 

 with the fern-like shoots produced when the top of a Carrot (partly 

 stem, partly root) is cut off, scooped out, filled with water, and hung 

 up by strings ; try this simple experiment for yourself. 



177. Sycamore (see Art. 392) ^ Examine twigs at 

 different times of the year, noting the arrangement of the 

 leaves, and therefore of the axillary buds, in crossed pairs, 

 forming four rows on the stem (Fig. 49). The twigs are, in 

 the younger parts, grey- green to yellow-brown in colour and 

 are dotted with small lenticels. The leaf -scars are shallow, 

 V-shaped, with three slight projections (bundle-scars). The 

 buds are egg-shaped, with four projecting ridges owing to 

 the boat-like form of the bud- scales. The scales, which are 

 arranged in opposite pairs, overlapping each other regularly, 

 are greenish below and brown at the tips and around the 

 edge. The large end-bud, which generally has two small 

 side-buds just below it, frequently contains an inflorescence 

 in addition to young foliage-leaves. 



Dissect a bud, carefully removing the parts and laying them out on 

 a sheet of paper. Note that there are six or seven pairs of scales 

 altogether, though only four or five pairs are, as a rule, visible on the 

 outside of the bud. How do the inner scales differ from the outer ones 

 in colour and texture ? Examine the tips of the scales : do any show 

 here a small undeveloped leaf -blade, with three or five lobes ? To what 



1 If you do not know these trees in their winter aspect, cut twigs 

 and put them into bottles or jars of water and keep them in a warm 

 room ; in many cases the buds will open, since warmth hastens growth. 

 In this way you can study very conveniently the unfolding of buds 

 (sketch the stages observed) and at the same time identify unknown 

 trees or shrubs oy the leaves in many cases. 



