lichenes


Значение термина lichenes в knolik


lichenes - lichenes
lichenes - Lichens, dual organisms formed from symbiotic association of two plants, a fungus and an alga. The fungus partner is usually an Ascomycete, sometimes a Basidiomycete, the algal partner a green (Chlorophyta) or blue-green (Cyanophyta) alga. A cosmopolitan group of plants occurring on tree trunks, old walls, on the ground, exposed rock, etc., and providing the dominant flora in large areas of mountain and arctic regions where few other plants can live. Lichens play an important part with liverworts and mosses in the primary colonization of bare areas. Lichens are crustose, forming a thin, flat crust on the substratum, foliose, flat with leaf-like lobes, or fruticose, upright, branched forms. Very slow growing and vary greatly in size, e.g. from a millimetre to several metres across. Reproduce vegetatively by soredia, groups of fungal hyphae enclosing algal cells, cut off and dispersed in large numbers. Sexual reproduction is confined to fungus partner and in majority of lichens it is by the development of apothecia or perithecia. On germination of the ascospores new lichen plants are formed if the algal partner happens to be present but in its absence the fungus dies.

In Arctic regions certain lichens are valuable as a source of food, e.g. Iceland moss, reindeer moss. Other lichens provide dyes, e.g. Roccella, providing litmus.

Рядом со словом lichenes в knolik


lianesВ начало
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life cycle

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