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Lichen morphology describes the external appearance and structures of a lichen. These can vary considerably from species to species. These can vary considerably from species to species. Lichen growth forms are used to group lichens by "vegetative" thallus types, and forms of "non-vegetative" reproductive parts.
Lichens grow in a wide range of shapes and forms; this external appearance is known as their morphology. The shape of a lichen is usually determined by the organization of the fungal filaments. [35] The nonreproductive tissues, or vegetative body parts, are called the thallus. Lichens are grouped by thallus type, since the thallus is usually ...
A gelatinous lichen, also widely known as a "jelly lichen", is one with a cyanobacterial species ("blue-green alga") as the principal photobiont. Chains of the photobiont, rather than fungal hyphae, make up the bulk of the thallus, which is unlayered (and undifferentiated) as a result. [43] Such lichens lack a cortex. [44]
Also cladoniform lichen, dimorphic lichen. Also defined: primary thallus and secondary thallus . A lichen with a two-fold growth form that includes both a crustose , squamulose , or foliose form and a fruticose form; the thallus differentiates into both horizontal (primary thallus) and vertical (secondary thallus, or podetium ) structures.
Usnea filipendula – one of about 20,000 described species of lichen. The following outline provides an overview of and topical guide to lichens.. Lichen – composite organism made up of multiple species – a fungal partner, one or more photosynthetic partners, which can be either green algae or cyanobacteria, and, in at least 52 genera of lichens, a yeast. [1]
Terms of plant morphology are included here as well as at the more specific Glossary of plant morphology and Glossary of leaf morphology. For other related terms, see Glossary of phytopathology , Glossary of lichen terms , and List of Latin and Greek words commonly used in systematic names .
The definition finally adopted was that lichen could be considered as the association between a fungus and a photosynthetic symbiont resulting in a thallus of specific structure. [ 26 ] Such a simple a priori definition soon brought criticism from various lichenologists and there soon emerged reviews and suggestions for amendments.
They are caused when there is a break in the cortex of the lichen, and the medullary hyphae extend to the surface. Pseudocyphellae are the same colour as the medulla of the lichen, which is generally white, but can be yellow in some species of Pseudocyphellaria and in Bryoria fremontii. The presence/absence, abundance, colour, and shape of ...