Fig. 37.—Horse Chestnut twig in winter.
(× ¹⁄₁₁.)		 Fig. 38.—The terminal part of a Horse Chestnut twig in winter.
l.s., leaf-scars; v.b., ends of food-pipes. (× ⅔.)

A year’s growth.—When the bud scales drop off they leave, as we have seen, a series of closely-set rings of scars. The distance between one set of rings and the next (as at R., [Fig. 34]), therefore represents a year’s growth. The student should get a twig two or three feet long and find out for himself, by examining the marks on it, what the twig did last year, two years ago, and three years ago. With care he will be able to say definitely in which year any fairly recent side-twig began to grow out from its bud.

A horse chestnut twig.—A winter twig of horse chestnut ([Fig. 37]) is very similar in its general features to what we have seen in the sycamore. The buds are in pairs at right angles to each other, and below each bud is a large corky leaf scar (l.s. [Fig. 38]), with the positions of the former food-pipes marked by black dots (v.b.). These buds, however, are larger than those of the sycamore, and each is covered with a shining layer of resin, to keep out insects and the rain.

We may slip the end of a penknife under the bud scales and remove them one by one. The first few are thin and papery, and soaked in resin. Those next inside are woody and much thicker. Next comes a layer of papery scales, inside that a coat of cottony down, then another soft papery layer, and lastly a thick pad of down. When we carefully scrape away this down, we find—warm and cosy in its midst—a tuft of little objects with a most quaint resemblance to hands clad in woollen gloves. We remove one of these, and on scraping it gently with a knife we see that the “hand” has seven fingers; and it presently becomes clear that each finger is a tiny green leaflet folded on itself, and that the hand is a young leaf. If we take off these gloved leaves in turn one by one, we find as we proceed that they become smaller, until they are almost too small to be distinguished in their fluffy nest. And when all the down and the baby leaves are scraped away, the tender growing point of the twig is left alone at the summit of a little cone, with steps showing where the leaves were.

Had the twig been left undisturbed on the tree, the bud would have awakened in spring and begun to grow ([Fig. 39]).[7] The scales and the down would have been shed, leaving only the rings of scars as a memento of the winter sleep; the growing point would have pushed on and on, lengthening perhaps a foot or more in three weeks; the leaves would have opened their bright green fingers to the spring air, and begun their work ([Fig. 40]), only to cease when in the autumn they too dropped off, and the new buds tucked themselves up in their beds to go to sleep. The leaves of the horse chestnut fall off, as do those of the sycamore, owing to a “separation-layer” arising at the base of the leaf stalk ([Fig. 41]), and in this case each leaflet also becomes separately detached in the same way.

Fig. 39.—Later stage of the Horse Chestnut
twig of Fig. 37. (× ¹⁄₉.)		 Fig. 40.—The later development of the terminal
bud of the twig of Figs. [ 37] and 39. (× ⅕.)

Other forms of buds.—Surrounding the young silky-fringed leaves of the beech bud are several crimson membranous scales which are really the stipules ([p. 43]) of undeveloped leaves. The thin, soft parts of the leaf blade are sharply pleated ([Fig. 42]) between the side veins which spring from the midrib.