The Ferns (Filices) are a natural order of cryptogamous or flowerless plants, forming the highest group of the acrogena or summit-growers. They are leafy plants, the leaves, or more properly fronds, arising from a rhizome or root-stock, or from a hollow arborescent trunk, and being circinate in vernation, a term descriptive of the manner in which the fronds are rolled up before they are developed in spring, having then the appearance of a bishop's crosier. On the veins of their lower surface, or their margins, the fronds bear small vessels named sporangia, containing spores. These spore-cases are arrangod in clusters, named sori, which are either naked or covered with a layer of the epidermis, which forms an involucre or indusium. When the spores germinate they produce a cellular structure of a leafy description, called the pro-embryo, or prothallus, upon which are developed organs which have received the names of antheridia and archegonia. When produced upon the prothallus these organs do not immediately give origin to a germinating spore, but from their mutual action proceeds a distinct cellular body, destined at a later period to develop into a fruit-bearing frond.
Ferns have a wide geographical range, but are most abundant in humid, temperate, and tropical regions. In the tropical forests the tree-ferns rival the palms, rising sometimes to a height of 15 or 18 metres. Ferns are very abundant as fossil plants. The earliest-known forms occur in Devonian rocks. Various systems of classification for ferns have been proposed over time. The order is usually divided into six or eight suborders or tribes distinguished by differences in the structure of the sporangium. The generic characters are founded on the position and direction of the sori and on the venation. The largest division is that of the Polypodiaceae, to which nearly all British ferns belong, such as the polypody, the lady-fern, the bracken, the hard-fern, the spleenwort, the maiden-hair, the hart's-tonguefern, etc. The royal fern, however, belongs to the Osmundaceae. A few of the ferns are used medicinally, mostly as demulcents and astringents. Some yield food. Pteris esculenta is the edible bracken of New Zealand. Research Ferns
Cornwall or Kernow (recorded in the Domesday Book as Cornualia) is a maritime county in south west England, forming the south-western extremity of the island, bounded east by Devon, and surrounded on all other sides by the sea; area. The coastline is much broken. Mount's Bay, Falmouth Bay and Harbour, Whitesand Bay, Fowey Harbour, and St Austell Bay are the principal openings on the south coast. The indentations on the north consist of, shallow bays with few or no harbours. Between these two coasts is the promontory of Land's End, terminating in granitecliffs about 60 feet high. Some of the other cliffs exceed 400 ft. in height. At Land's End terminate the hills of the Devonian Range. The part of this range belonging to Cornwall stretches from north-east to south-west, forming the principal watershed of the county. Its highest summit is Brown Willy, 1868 ft. Granite and old red sandstone are the chief rocks.
The rivers are numerous but short. Much of the area, especially in the elevated districts, is barren moorland. The chief wealth of the county was traditionally in its minerals, especially its mines of copper and tin, though the value of both greatly sunk since the 19th century and by the late 20th were of no consequence. Several mines exceeded 350 fathoms in depth. In the BotallackCopperMine, a few miles north of Land's End, the workings were carried below the sea. Besides tin and copper, silver, lead, zinc, iron, manganese, antimony, cobalt, and bismuth are found in comparatively small quantities. There are also valuable deposits of kaolin or china-clay. The fisheries, particularly of pilchard and mackerel, have long been a valuable part of Cornwall's economy.
Cornwall, with the Scilly Isles, seems to have been the Cassiterides or Tin Islands of antiquity. The natives long maintained their independence against the Saxons, and their country was spoken of as West Wales. Their language also long continued to be Celtic. Cornwall gives the titleDuke of Cornwall to the eldest son of the sovereign of Great Britain, and forms a royal duchy, the revenues of which belong to the Prince of Wales for the time being. The dukedom was created for the Black Prince in 1337.
Abbreviations
Research Ferns
