182
andrias, 19
(2012)
The genus Rhizodiscina H
afellner
(Patellariales,
Dothideomycetes) is superficially rather similar to
Dactylospora and Deltopyxis. It is characterized
by faintly euamyloid or sometimes inamyloid, sac-
cate, 8-spored asci with a thick inamyloid tholus,
brown, 1-septate ascospores, and projecting,
brown, 3-4.5 µm wide anchoring hyphae.
Quite a lot of genera of Helotiales (Leotiomycetes)
with small, sessile, blackish apothecia bear some
similarity with Deltopyxis. However, the rather
saccate asci in Deltopyxis seem to indicate that
this genus does not belong to the Helotiales. Five
mainly lichenicolous genera with black apothecia
are in the following compared with Deltopyxis:
Geltingia A
lstrup
& D. H
awksw
., Llimoniella H
a
-
fellner
& N
av
.-R
os
., Phaeopyxis R
ambold
& T
rie
bel
, Rhymbocarpus Z
opf
, and Skyttea S
herwood
,
D. H
awksw
. & C
oppins
. Skyttea differs in asci with
strongly thickened apical and thin lateral wall, also
in elongate, hyaline to brown, hair-like cells at
the protruding margin (S
herwood
, H
awksworth
&
C
oppins
1981). Hair-like structures are partly also
typical of Rhymbocarpus, in which the asci are not
or only slightly thick-walled at the apex.The genus
Llimoniella resembles Deltopyxis in the structure
of the ectal excipulum and the rather thin-walled
asci. It differs in a purplish pigment that turns vi-
olaceous in KOH, and in addition an olivaceous
pigment that turns bright green herein (D
iederich
& E
tayo
2000). The type species of Geltingia,
G. associata A
lstrup
& D. H
awksw
., strongly re-
sembles Deltopyxis in median section and in the
slightly thickened apical ascus wall with a slight
apical chamber, according to the redescription
by D
iederich
et al. (2010 Figs 2E, 5). Also Rhym
bocarpus aggregatus E
tayo
& D
iederich
(2011,
Fig. 1C-E) concurs in median section with Delto
pyxis. The asci in Phaeopyxis have an immature
overall thickened wall (laterally †1-1.5 µm thick,
apically †1.5-3.5 µm) and partly show a faintly
amyloid iodine reaction; the brown excipular and
hymenial pigment often stains ± violet-brown in
KOH (R
ambold
& T
riebel
1990).
A specimen of Phaeopyxis punctum (M
assal
.)
R
ambold
et al., identified by R. S
antesson
and G.
R
ambold
(H.B. 4341), was examined by us: the
(bluish) black-brown exudate did not change its
colour in KOH. In contrast to Deltopyxis, the apical
ascus wall did not stain in CR
SDS
.
All five genera differ from Deltopyxis in their
8-spored, rather narrowly cylindrical asci, in api-
cally not or only slightly inflated paraphyses in
which the terminal cells are generally about 5-10×
longer than wide, in a tendency of the paraphyses
to being branched at the uppermost septum or at
least towards the base, in ellipsoid-ovoid or cylin-
dric-oblong to fusiform ascospores with a usually
rather high lipid content, and in a mostly licheni-
colous habitat, the apothecia being often deeply
immersed or erumpent (except for Llimoniella).
A certain similarity is seen between Deltopyxis
and the type species of Patinella S
acc
., P. hy
alophaea S
acc
., which was placed with hesitation
by N
annfeldt
(1932) in the Orbiliaceae because of
capitate paraphyses and angular excipular cells,
and later in the Dermateaceae by S
pooner
(1987).
Reexamination of the type material (B
aral
ined.)
confirmed placement in the Helotiales, but its re-
lationship to a family is quite difficult to assess.
The apices of the narrow, 8-spored asci have a
pronounced inamyloid apical thickening, and the
strongly capitate, dark brown apices of the long
terminal cells of paraphyses appear as being
thick-walled. The spores have a similar size and
lipid content as in Deltopyxis but are ellipsoid.
The genera Claussenomyces K
irschst
. (in the
current circumscription) and Tympanis T
ode
fre-
quently possess polysporous asci, but this feature
is due to budding of 8 ascospores within the pre-
mature ascus, very different from Deltopyxis. Also
here the asci open by a large apical slit, but the as-
cus wall is congophilous laterally rather than api-
cally [observed in C. kirschsteinianus (K
irschst
.)
G. M
arson
& B
aral
and C. atrovirens (P
ers
.) K
orf
& A
bawi
agg.]. Several further genera with black
apothecia exist in the Helotiales, but none of them
appears to be related to Deltopyxis.
There exist also some undescribed species of
Orbiliomycetes with black-olivaceous apothecia
and 8-16-spored asci (B
aral
et al. in prep.). Their
ascospores contain spore bodies that disap-
pear when KOH is added, whereas the drops in
the spores of Deltopyxis resist herein and are,
therefore, classified as lipid bodies. Moreover, the
asci have a furcate base without croziers, unlike
Deltopyxis. In its extraordinary spore shape, D.
triangulispora reminds of some undescribed spe-
cies of Orbilia F
r
. in which triangular spores actu-
ally occur, but particularly the absence of a spore
body and the fact that small conidia bud from the
ascospores make such relationship highly im-
probable. Like Deltopyxis, the asci of Orbilia open
by an apical slit; yet, it was never the ectotunica
that stained in CR
SDS
, but instead the endotunica
showed a congophilous reaction in species with a
thick-walled ascus apex.
Phylogenetic placement: A sequence of the ITS1-
5.8S-ITS2 rDNA gained from pure culture (H.B.
