. Field and woodland plants. theyhave emerged from thebud ; and as soon asthe epidermis is suffi-ciently impermeablethe stipules, havingdone their work, fallto the ground. Sogreat is the shower ofthese transient struc-tures, in the case ofthe Oak, Ehn, andLime trees, that theground is almost com-pletely covered bythem. Young leaves haveyet another way ofpreventing the evap-oration of their sap,and that is by turningthemselves into the erect position so that the warmth of thespring sun has but little effect on them. The young leaves ofvarious grasses turn their apices upwards ; while those of t
. Field and woodland plants. theyhave emerged from thebud ; and as soon asthe epidermis is suffi-ciently impermeablethe stipules, havingdone their work, fallto the ground. Sogreat is the shower ofthese transient struc-tures, in the case ofthe Oak, Ehn, andLime trees, that theground is almost com-pletely covered bythem. Young leaves haveyet another way ofpreventing the evap-oration of their sap,and that is by turningthemselves into the erect position so that the warmth of thespring sun has but little effect on them. The young leaves ofvarious grasses turn their apices upwards ; while those of theHorsechestnut, after having lost the i:)rotection afforded by thewoolly covering and the original folding, turn themselves withtheii- points downwards. Later, when the epidermis is wellformed, and the leaves are so far developed that they are capableof utilising the energy of the sun in the performance of theirfunctions, they take up the horizontal position. Another interesting matter for spring observation is the relative. Twig op the lime in Spring, showing the DECIDUOUS, SCALY STIPtlLES. 46 FIELD AND WOODLASD PLANTS times of the bursting of the flowering buds and the leafing budson the same species of tree or shrub. In many cases the formerare fully developed before the latter show any signs of active growth, or while the foliage is as yet onlypassing through its earliest Hazel catkins shed their abund-ance of pollen before the foliage budsshow the slightest signs of green. TheBlackthorn is white with snowyblossoms before a leaf appears. The^^^. ^^^ upper twigs of the Elm appear fluffy ^I^W^^^^ in the distance through the formation ^^^y^^^B of its flowers while the foliage buds are I still dormant; and the Alder, Willow, \ Poplar and Aspen likewise produce full-blown catkins while theii- branchesare otherwise bare. Of the treesabove named, the Hazel, Elm, Alder,Poplar, and Aspen are dependent onthe spring winds for the transfer of thepollen, but the pollination
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