Basic structural characteristics:
There is considerable variation in morphological and structural characteristics of ectomycorrhizas, although three features are generally recognized to typify this association: the formation of a mantle or sheath of fungal hyphae that covers considerable portions of lateral roots; the development of hyphae between root cells to form a complex highly branched structure called the Hartig net; and hyphae that emanate from the mantle and grow into the surrounding soil (extraradical mycelium). In addition, some ectomycorrhizas develop linear aggregations of hyphae (rhizomorphs or strands) in the extraradical mycelium that are specialized for rapid transport of nutrients and water. The Hartig net in roots of most angiosperm species is confined to the epidermis, the cells of which enlarge radially, while in gymnosperms the epidermis and cortex are involved. The first two diagrams illustrate these features in longitudinal and transverse view, respectively. The third and fourth diagrams illustrate the labyrinthine branching of Hartig net hyphae.
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Diagrams
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 Longitudinal section
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 Transverse section
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 Hartig net cutaway
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 Hartig net surface
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Angiosperms
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 Alnus / Alpova
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 Alnus / Alpova
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 Alnus / Alpova
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 Alnus / Alpova
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 Alnus / Alpova
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 Alnus / Alpova
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 Alnus / Alpova
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 Betula / Laccaria
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 Betula / Laccaria
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 Betula / Laccaria
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 Betula / Laccaria
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 Betula / Laccaria
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 Betula / Laccaria
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 Betula / Paxillus
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 Betula / Pisolithus
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 Betula / Pisolithus
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 Betula / Pisolithus
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 Eucalyptus / Pisolithus
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 Eucalyptus / Pisolithus
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 Eucalyptus / Pisolithus
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 Eucalyptus / Pisolithus
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 Eucalyptus
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 Eucalyptus
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 Eucalyptus
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 Eucalyptus
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 Fagus / unknown
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 Fagus / unknown
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 Nothofagus
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 Nothofagus
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 Nothofagus
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 Polygonum / unknown
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 Polygonum / unknown
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 Polygonum / unknown
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 Dryas / Hebeloma
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 Dryas / Hebeloma
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Gymnosperms
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 Pinus / Pisolithus
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 Pinus / Pisolithus
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 Pinus / Pisolithus
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 Pinus / Laccaria
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 Pinus / Laccaria
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 Pinus / Piloderma
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 Pinus / Piloderma
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 Pinus / Piloderma
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 Pinus / Piloderma
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 Pinus / Piloderma
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 Pinus / Cenococcum
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 Pinus / Cenococcum
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 Pinus / Rhizopogon
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 Pseudotsuga
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 Pseudotsuga
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 Pseudotsuga
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 Pseudotsuga
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 Pseudotsuga
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 Picea / Cenococcum
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-
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