The group has until recent years been regarded as comprising three classes distinguished by well-marked physiological featuresthe Algae (including the Seaweeds) which contain chlorophyll, the Fungi which have no chlorophyll and therefore lead a saprophytic or parasitic mode of life, and the Lichens which are composite organisms consisting of an alga and a fungus living together in a mutual parasitism (symbiosis); Bacteria were regarded as a section of Fungi.
Owing to the similarity of structure and mode of life it is convenient to treat the Lichens (q.v.) as a distinct class, while recognizing that the component fungus and alga are representatives of their own classes.
This is especially the case in the lichens (symbiotic organisms composed of a fungal mycelium in association with algal cells), which are usually exposed to very severe fluctuations in external conditions.
This is particularly marked in certain lichens of shrubby habit.
Since about 1880 our knowledge of the species which can enter into such relationships has been materially extended, and the fungal constituents of the Lichens are known to include Basidiomycetes as well as Ascomycetes.
~any Algae, lichens, and mosses are included among lithophytes, ai id also Saxifraga Aizoon, S.
In the Florideae, Lichens and Laboulbenjaceae the, male cell is a non-motile spermatium, which is carried to the female organ.
(2) The tundra or region of intensely cold winters, forbidding tree-growth, where mosses and lichens cover most of the ground when unfrozen, and shrubs occur of species which in other conditions are trees, here stunted to the height of a few inches.
Mosses and lichens are distinctive, as also are the birch, the dwarf willow and several shrubs; but where the soil is drier, and humus has been able to accumulate, a variety of herbaceous flowering plants, some of them familiar in W.
Still, the reindeer frequents it for its lichens, and on the drier slopes of the moraine deposits there occur four species of lemming, hunted by the Arctic fox (Vulpes lagopus).
They feed chiefly on grass, but also on moss, lichens and tender shoots of the willow and pine.
Taught the people how to prepare dyes from the plants and lichens, and many of the patterns still show signs of Moorish origin.
Lichens are generally mounted on sheets of paper of the ordinary size, several specimens from different localities being laid upon one sheet, each specimen having been first placed on a small square of paper which is gummed on the sheet, and which has the locality, date, name of collector, &c., written upon it.
Lichens for the herbarium should, whenever possible, be sought for on a slaty or laminated rock, so as to procure them on flat thin pieces of the same, suitable for mounting.
Many lichens, such as the Verrucariae and Collemaceae, are found in the best condition during the winter months.
Those fungi which are of a dusty nature, and the Myxomycetes or Mycetozoa may, like the lichens, be preserved in small boxes and arranged in drawers.
Below the mountain crests, where only the hardiest lichens and mosses can survive, comes a belt of large timber, including many giant trees, 200 ft.
The last trees which struggle for existence on the verge of the tundras are crippled dwarfs and almost without branches, and trees a hundred years old are only a few feet high and a few inches through and thickly encrusted with lichens.'
In the alpine tracts of the north the narrowness of the valleys and the steep stony slopes strewn with debris, on which only lichens and mosses are able to grow, make every plot of green grass (even if it be only of Carex) valuable.
AaK6s, a bag), a botanical term for the membranous sacs containing the reproductive spores in certain lichens and fungi.
The flora consists of 129 species of angiosperms, i Cycas, 22 ferns, and a few mosses, lichens and fungi, 17 of which are endemic, while a considerable number - not specifically distinct - form local varieties nearly all presenting Indo-Malayan affinities, as do the single Cycas, the ferns and the cryptogams. As to its fauna, the island contains 319 species of animals-54 only being vertebrates-145 of which are endemic. A very remarkable distributional fact in regard to them, and one not yet fully explained, is that a large number show affinity with species in the Austro-Malayan rather than in the Indo-Malayan, their nearer, region.
It is found in the form of its acid potassium salt in many plants, especially in wood-sorrel (Oxalis acetosella) and in varieties of Rumex; as ammonium salt in guano; as calcium salt in rhubarb root, in various lichens and in plant cells; as sodium salt in species of Salicornia and as free acid in varieties of Boletus.
Hooker enumerated twenty-one species of flowering plants, and seven of ferns, lycopods, and Characeae; at least seventyfour species of mosses, twenty-five of Hepaticae, and sixty-one of lichens are known, and there are probably many more.
On the summits of the Adirondacks are a few alpine species, such as reindeer moss and other lichens; on the shores of Long Island, Staten Island and Westchester county are a number of maritime species; and on Long Island are several species especially characteristic of the pine barrens of New Jersey.
Structural, having reference to the form and structure of the various parts, including (a) Morphology, the study of the general form of the organs and their development - this will be treated in a series of articles dealing with the great subdivisions of plants (see Angiosperms, Gymnosperms, Pteridophyta, Bryophyta, Algae, Lichens, Fungi and Bacteriology) and the more important organs (see Stem, Leaf, RooT, Flower, Fruit); (b) Anatomy, the study of internal structure, including minute anatomy or histology (see Plants: Anatomy).
As it flows it takes the forms of sappy leaves or vines, making heaps of pulpy sprays a foot or more in depth, and resembling, as you look down on them, the laciniated, lobed, and imbricated thalluses of some lichens; or you are reminded of coral, of leopard's paws or birds' feet, of brains or lungs or bowels, and excrements of all kinds.