on the bark of trees, take much nourishment from them; hence it is
observed that trees, which are annually cleared from moss by a brush,
grow nearly twice as fast. (Phil. Transact.) In the cyder countries the
peasants brush their apple-trees annually.]

[_Zostera_. l. 266. Grass-wrack. Class, Feminine Males. Order, Many
Males. It grows at the bottom of the sea, and rising to the surface, when
in flower, covers many leagues; and is driven at length to the shore.
During its time of floating on the sea, numberless animals live on the
under surface of it; and being specifically lighter than the sea water,
or being repelled by it, have legs placed as it were on their backs for
the purpose of walking under it. As the Scyllcea. See Barbut's Genera
Vermium. It seems necessary that the marriages of plants should be
celebrated in the open air, either because the powder of the anther, or
the mucilage on the stigma, or the reservoir of honey might receive injury
from the water. Mr. Needham observed, that in the ripe dust of every
flower, examined by the microscope, some vesicles are perceived, from
which a fluid had escaped; and that those, which still retain it, explode
if they be wetted, like an eolopile suddenly exposed to a strong heat.
These observations have been verified by Spallanzani and others. Hence
rainy seasons make a scarcity of grain, or hinder its fecundity, by
bursting the pollen before it arrives at the moist stigma of the flower.
Spallanzani's Dissertations, v. II. p. 321. Thus the flowers of the male
Vallisneria are produced under water, and when ripe detach themselves from
the plant, and rising to the surface are wafted by the air to the female
flowers. See Vallisneria.]


The silvery sea-weed matted round her bed,
And distant surges murmuring o'er her head.--