An abstract from:

A poem, in two parts.

Part II.

The loves of the plants

1798

Stretch'd on her mossy couch, in trackless deeps,

Queen of the coral groves, Zostera sleeps;

The silvery sea-weed matted round her bed,

And distant surges murmuring o'er her head.---

High in the flood her azure dome ascends,

The crystal arch on crystal columns bends;

Roof'd with translucent shell the turrets blaze,

And far in ocean dart their colour'd rays;

O'er the white floor successive shadows move,

As rise and break the ruffled waves above.---

Around the nymph her mermaid-trains repair,

And wave with orient pearl her radiant hair;

With rapid fins she cleaves the watery way,

Shoots like a silver meteor up to day;

Sounds a loud conch, convokes a scaly band,

Her sea-born lovers, and ascends the strand.

Explains Darwin:

Zostera. 1. 264. 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, numberless animals live on or under the surface of it; and being specifically lighter than 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 Scylloea. See Barbutís Genera Vermium. It seems necessary that the marriage of plants should be celebrated in the open air, either because 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 under the microscope, some vesicles are perceived, from which a fluid had escaped; and that those that still retain it, explode if they are wetted, like an eolopile suddenly exposed to strong heat. The 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 flowers. Spallanzaniís Dissertations, v. xi. p. 321. Thus the flower of the male Valisneria are produced under water, and, when ripe, detatch themselves from the plant, and, rising to the surface, are wafted by the air to the female flowers.

Erasmus Darwin was the grandfather of Charles Darwin. He was a well respected naturalist in his own right.