SUBGENERIC TAXA OF HYPOXYLON
| Two subgeneric taxa of Hypoxylon are accepted by us: section Hypoxylon and section Annulata. These two sections are primarily differentiated by the presence or absence of a layer of carbonaceous stromatal tissue enclosing perithecia. When the perispore of ascospores is dehiscent and when the ostiolar discs are present, they also provide additional major characters to separate these two sections. Only taxa of section Hypoxylon possess coil-like ornamentation on the perispore, and only those of section Annulata possess a localized thickening on the perispore. Annulate ostiolar discs are found exclusively in section Annulata. | ||
| 1. Carbonaceous stromatal material surrounding individual
perithecia absent.
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1. Carbonaceous stromatal material surrounding individual
perithecia present.
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| 2. Ostioles usually lower than the level of
stromatal surface, less frequently at the same level or slightly higher than the level of
stromatal surface, never encircled with an annulate disc.
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2. Ostioles always higher than the level of
surrounding stromatal surface, encircled with an annulate disc except in H.
cohaerens, H. multiforme
and their respective varieties, and H. nothofagi.
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| 3. Perispore, when dehiscing, with conspicuous to
inconspicuous transverse coil-like ornamentation visible.
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3. Perispore, when dehiscing, with a thickened area visible
at the position of ca. 1/3 ascospore length on the same side as the germ slit.
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