6 Wood Discoloration

2.2 Growth and Spreading 23
surface enlargement the hymenium may be e.g., net-like arranged (merulioid,
S. lacrymans), warted (C. puteana), porous (A. vaillantii), or lamellate (Armillaria
mellea). In the young basidium (Fig. 2.15H), karyogamy (I) and meiosis
(J)occur.Fourhaploidnucleimigrateintooutgrowths(sterigmata)atthetop
of the basidium (K) and are discharged as basidiospores.
The spore size (5–20µm), shape (globose, cylindric, ellipsoid etc.), surface
sculpturing (“ornamentation”: warted, crested, etc.), wall-thickness (thinwalled,
double wall) (Ryvarden and Gilbertson 1993) and color (colorless or
pigmented: white, yellow, orange, ochre, pink, brown, green, violet, black)
are taxonomic characteristics. In the microscope, spores appear frequently
bright to colorless (hyaline), e.g., in Daedalea quercina, Fomes fomentarius,
H. annosum, Laetiporus sulphureus, Piptoporus betulinus and Trametes versicolor.
Brownish spores separate e.g., the genus Serpula from other fungi with
merulioid hymenium (Pegler 1991). Further characteristics are the violetstaining
of amyloid spores (e.g., Stereum sanguinolentum)andthebrown-red
staining of dextrinoid spores by JJK as well as the blue-staining of cyanophilic
spores (C. puteana, H. annosum, Oligoporus placenta) by aniline blue (e.g., Erb
and Matheis 1983).
For the differentiation of the various fruit body types serve, e.g., the occurrence
of sterile cells (cystidia) between the basidia (e.g., Antrodia spp.
and Gloeophyllum spp.) and the construction of basidiocarps consisting of
vegetative hyphae (monomitic), additionally of either skeletal or binding hyphae
(dimitic) or of all three hyphal types (trimitic). Monomitic genera are
Coniophora, Meripilus and Phaeolus, dimitic are Antrodia, Heterobasidion,
Hirschioporus, Laetiporus and Phellinus, and trimitic are Daedalea, Fomes and
Trametes.
Most wood-inhabiting Basidiomycetes belong to the Homobasidiomycetes
(formerly Holobasidiomycetes: single-celled basidium) and there to the Aphyllophorales
with gymnocarpous (hymenium exposed while spores are still im-
Fig.2.17. Common types of fruit bodies of wood-inhabiting Basidiomycetes. a Pileate with
central stipe (Lentinula edodes cultured on wood by J. Liese in 1935). b Bracket-like (Piptoporus
betulinus on a birch tree, photo T. Huckfeldt). c Resupinate (Serpula lacrymans in
a building)
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