Introduction to Fungi, Third Edition

444 HYMENOASCOMYCETES: HELOTIALES (INOPERCULATE DISCOMYCETES)
Fig15.11 Trichoglossum hirsutum. (a) Apothecia. (b) Asci,
ascospores, paraphyses and a hymenial seta.
rapidly discharged. Another ascospore immediately
takes the place of the first spore and the
process of discharge is continued until all eight
ascospores have been released in single-file
(Ingold, 1953).
15.5.2 Leotiaceae
Following the separation of the Helotiaceae
(see below), the Leotiaceae now represent only
a small group (13 species) of saprotrophic fungi.
They can be distinguished from the Geoglossaceae
by their brightly coloured ascocarps
and hyaline ascospores (Lizoň et al., 1998).
A well-known example is Leotia lubrica (Plate 7f),
a species colonizing woodland humus and
known colloquially as ‘jelly babies’.
15.5.3 Helotiaceae
Even after the separation of the Leotiaceae, this
is still a very large (4600 spp.) and probably
polyphyletic group. Well-known and widely distributed
saprotrophic genera are Ascocoryne and
Neobulgaria which produce gelatinous pinkish
apothecia on relatively fresh dead wood, or
Chlorociboria with its bright green apothecia
(Plate 7g). Chlorociboria spp. stain the colonized
wood, and this is sometimes used in furniture
making for ornamental inlays. Bisporella citrina
(Plate 7h) is another commonly encountered
species on relatively freshly fallen twigs.
Some members of the Helotiaceae,
notably Hymenoscyphus ericae, as well as some
other ascomycetes belonging to the Plectomycetes
(e.g. Pseudogymnoascus, Myxotrichum, Oidiodendron;
see p. 295), can form mycorrhizal
associations with ericaceous plants such as Erica
and Vaccinium. This association is called ericoid
mycorrhiza and has fundamentally different
properties from the vesicular arbuscular
(p. 202), ectomycorrhizal (pp. 525 and 581) and
orchid mycorrhizal types (p. 596). Ericaceous
plants form numerous small lateral roots called
hair roots which consist of a narrow vascular
bundle surrounded by a thin cortex and a thick
epidermal monolayer. When H. ericae infects
individual epidermal cells of its host’s hair
roots, it invaginates the plasmalemma and
forms hyphal coils which superficially resemble
those seen in orchid mycorrhiza (see Fig. 21.2).
Hymenoscyphus ericae is credited with making