Page:A Short Account of the Botany of Poole.djvu/9

Rh largest of these is Brownsea island, the watering residence of Sir Charles Chad, Bart., which, among many other natural beauties, possesses several fresh water tarns, similar to those of Parkstone and Creekmoor, one of which contains a great abundance of the Typha angustifolia, Lin. The woods in Brownsea abound with Listera ovata, Br.

The mouth of the harbour is about four miles from Poole, and is composed of two valvate sand banks; the external one, the South Haven bank, is connected with Purbeck, and the other, the North Haven, with the main land of Dorsetshire and Hampshire. These banks are maintained by the creeping roots of Ammophila arundinacea, Host., Carex arenaria, Lin., and Festuca rubra, Lin. The beach on both havens is fine hard sand, and from the North Haven continues so to the east, but from the South Haven point following the coast, the chalk and succeeding inferior strata make their appearance, and the beach is soon lost in the steep and high cliffs, which characterize the coast of Purbeck. Before, however, the beach is lost, it becomes changed from sandy to pebbly, which is its character in Studland bay.

There is a striking difference between the botany of the harbour, and that of the open sea beach:—the same plants are rarely met with in the two situations: Juncus maritimus, Sm., and Carex extensa, Good., are remarkable exceptions. Atriplex patula is found both on the muddy shore of the harbour, and on the sandy beach of the open sea; but the varieties are remarkably different.

The Ballast quay at Ham, opposite Poole, frequently yields plants, not elsewhere found in the neighbourhood. Linum usitatissimum, Lin., Sinapis tenuifolia, Br., S. muralis, Br., Cynosurus echinatus, Lin., and Medicago denticulata, Willd., are the principal. Trifolium resupinatum, Lin., found near this quay, must, I fear, be attributed to the ballast.