THE HEDGE MAPLE— continued. 
North American species. It is this which gives them, when gathered green and 
dried, some value as winter provender for cattle. 
The three most distinctive characters of the species are the form of the leaves, 
the erect flower-clusters, and the direction and shape of the wings of the fruit. The 
inflorescences terminate the young shoots of the year, the flowers opening in a 
racemose or sub-corymbose sequence. Peduncles, sepals, anthers, and ovaries are 
alike downy, so as often to appear as if thickly covered with dust ; and, incon- 
spicuous among the young leaves in May and June, the flowers are, in spite of their 
honey, but little visited by insects. The lower flowers in the cluster are male, 
producing perfectly functional stamens, but only the rudiment of an ovary. Those 
terminating the cluster may be functionally female, having anthers which do not 
mature, or perfectly bisexual, in which case they are sometimes protandrous. 
Pollination seems to be commonly effected by wind, but sometimes by flies and 
occasionally autogamously, i.e. by the pollen of the same flower. 
The hairy ovary at an early stage of its development shows signs of the wings 
that are to grow from the side of each carpel. Of these, though two is the usual 
number, three not uncommonly occur. The wings grow out like the two blades of 
a screw-propeller, and the study of their outlines and relative positions in the 
various species of the genus has proved of service to the marine engineer. In our 
species, however, the propeller seems of a somewhat primitive, i.e. unelaborated, 
type, its wings spreading in one horizontal line and each having a simple, oblong 
outline. When, in October, the fruit is ripe, and is torn off by wind, the propeller 
does not spin so readily, as it falls to the ground, as does the more specialised 
structure in the Sycamore ; and consequently does not so readily secure the 
dispersal of the fruit horizontally, away from the shadow of the parent tree, by the 
lightest of breezes. While the wings become glabrous, the attached seed-containing 
carpel may either remain downy, in which case the variety has been named A. campestre , 
var. hebecarpum De Candolle, or become glabrous, when it is the var. leiocarpum of 
Wallroth : the former is certainly the more frequent. 
The seed is exalbuminous, and the strap-shaped cotyledons are rolled up and 
already green within the brown fruit ; but their germination is often much delayed. 
The leaves of the Maples in our hedgerows often exhibit various diseases : 
they may be spotted with black by the attacks of one fungus, or hoary, as if covered 
with powdered chalk, by the action of another ; thickly studded with red galls 
produced by a mite, or glazed with the honey-dew resulting from aphides. 
