13 Dacrymycetes
FRANZOBERWINKLER^1
CONTENTS
I. Introduction............................... 357
II. Ontogeny................................... 358
III. Basidiocarp Morphology.................. 359
IV. Hyphal Systems, Hyphae, Marginal Hairs,
and Hyphal Septa.......................... 360
V. Hymenia, Dikaryophyses, Basidia, and
Basidiospores.............................. 360
VI. Anamorph Stages.......................... 362
VII. Wood Decay, Substrate Specificity, and
Distribution................................ 363
VIII. Traditional Taxonomy.................... 364
IX. Molecular Phylogenies.................... 368
X. Conclusions................................ 370
References.................................. 370
I. Introduction
Dacrymycetes is a well-defined class in the
Agaricomycotina, Basidiomycota. The most
important characteristic of this class is its
unique basidial ontogeny and morphology
(Fig.13.1d). Young basidia grow to become
slightly clavate and expand apically to produce
two thick, cylindrical, and long sterigmata that
taper abruptly to form spicula on which large
asymmetrically attached spores develop.
Between the sterigmata the original apex of
the young basidium remains visible, a charac-
teristic that is morphologically rather distinc-
tive. Most species have curved-cylindrical
basidiospores that are typically transversely
septate when mature (Fig.13.1e–g). Basidios-
pores commonly germinate with microconidia
(Fig.13.1e, f), but germ-tube formation is also
widespread (Fig.13.1g). The production of sec-
ondary spores is not known in Dacrymycetales.
Several species ofDacrymyces,Femsjonia,Gue-
piniopsis, andCalocera, which have been stud-
ied extensively in pure culture, producelimited
yeast coloniesthat originate from microconidia
(Fig. 13.1f). Microconidium formation also
occurs on hyphae (Fig.13.1h) and functions as
additional asexual reproduction. InDacrymyces
stillatus, hyphal fragmentation, also considered
a conidial stage, is rather common and serves as
an effective dispersal mechanism (Fig.13.1i).
Hyphal walls partly gelatinize, thereby forming
a soft waxy to gelatinous, sometimes tough,
consistency. Basidiocarp morphology varies
from strictly corticioid to pustulate, cupulate,
cyphelloid, stalked-capitate, or clavarioid. The
abhymenial surfaces often produce strongly
differentiated so-called marginal hairs, which
are terminal hyphal cells that are characteristic
of certain taxa. Cystidia are absent in the hyme-
nia, but conspicuously branched dikaryophyses
often occur. Dacrymycetes species form pre-
dominantly gelatinous,mostly bright yellowish
to orange basidiocarpsthat are pigmented by
carotenoids. Most fructifications have rootlike
bases in the wood; rarely are they broadly
attached to the substrate. An intensive brown
rot is associated with growth in coniferous and
angiosperm wood, but lignin decomposition
may also occur.(^1) Institut fu ̈r Evolution und O ̈kologie, Universita ̈tTu ̈bingen,
Auf der Morgenstelle 1, 72076 Tu ̈bingen, Germany; e-mail:
[email protected]
Systematics and Evolution, 2ndEdition
The Mycota VII Part A
D.J. McLaughlin and J.W. Spatafora (Eds.)
©Springer-Verlag Berlin Heidelberg 2014