44 HOUSE, GARDEN, AND FIELD 



X. THE SUMMER DROOP OF BOUGHS. 



From my study window I look out upon a lime-tree, 

 and have abundant opportunity of observing how it 

 changes its aspect according to the time of year. In 

 summer its leafy boughs form gently drooping sheets, 

 which rise and fall in the breeze, swaying gracefully as if 

 loaded with no more weight than they can easily carry. 

 In winter the branches rise again ; being now bare of 

 leaves, they form an open network which gives little hold 

 to the wind. The buds, arranged first on one side and 

 then on the other, show that future extensions will all 

 lie in the same plane. Evidently the slender boughs of 

 the lime droop in summer because they are weighted with 

 foliage. A single lime-leaf weighs about half a gram, and 

 on one good-sized bough I counted more than two thou- 

 sand leaves distant fifteen feet or more from the main 

 trunk ; that is to say, two kilograms (over four pounds) 

 of leaves were borne on the narrow end of a bough 

 upwards of fifteen feet long. No wonder that the bough 

 droops. In a friend's house there is a window which is 

 darkened in summer by the leafy boughs of a sycamore ; 

 in winter not a twig of the sycamore can be seen from 

 that window. Boughs have been known to break by the 

 mere weight of the leaves in places not exposed to wind. 

 Mr. Miller Christy l remarks that a horse-chestnut in his 

 garden causes no obstruction to a path beneath in winter, 

 when the boughs are bare, but that in summer a certain 

 bough interferes very inconveniently with free passage 

 along the path. This led him to note the height of the 

 branch above the path during three years. The tree was 

 forty feet high, and the branch in question measured 

 28 ft. 6 in. in length, and had a circumference of 26 in. 

 where it left the bole. The annual droop of this bough 

 amounts to about ten inches, attaining its maximum in 



1 Journ. Linn. Soc. t Botany, 1898, pp. 501-7. 



