Trichoconis

Abstract

The genus Trichoconis currently comprises two lichenicolous species: T. lichenicola, confined to Peltigera species, and T. physciicola, known from various corticolous hosts. Trichoconis hafellneri is regarded as a synonym of T. physciicola.

Full text

483
Trichoconis
Trichoconis Clem.
Gen. Fungi: 145, 176 (1909). Type: T. caudata (Appel & Strunk)
Clem.
Molecular data: yes. Number of species: 2–0–0 (20).
Colonies euse, hyaline. Mycelium immersed or super-
cial; stromata and setae lacking. Conidiophores ma-
cronematous, mononematous, solitary to loosely aggre-
gated, hyaline, single or branched. Conidiogenous cells
integrated, terminal, hyaline, polyblastic, sympodial, den-
ticulate, with cylindrical denticles. Conidia solitary, dry,
aseptate or septate, hyaline, fusiform, obclavate, clavate,
ellipsoidal, subcylindrical or navicular, apical and lateral,
in many species rostrate; conidial secession rhexolytic.
Notes. Keys to the species are provided by Braun et al.
(2016) and Silva et al. (2015).
Ecology. On plants, plant debris and fungi, including lichens.
Trichoconis lichenicola D. Hawksw.
Trans. Brit. Mycol. Soc. 74: 382 (1980). Type: Ireland, Co. Kerry,
Killarney, Torc Cascade, on Peltigera didactyla, March 1976,
R. G. Woods (K IMI238627 – holotype).
Colonies euse, loose, whitish. Mycelium immersed, of
hyaline hyphae, 2.5–4 μm wide. Conidiophores arising lat-
erally from the mycelium, straight, unbranched, hyaline,
smooth-walled, 0–2-septate, 30–50 × 3.5–5 μm. Conidio-
genous cells integrated, terminal, polyblastic, hyaline,
smooth-walled, cylindrical, with parts of separating cells
adhering or scars where they have seceded, with 1 to sev-
eral conidia arising at a single time; separating cells cylin-
drical, 5–7 × 0.5–1 μm, delimited from the conidiogenous
cell and the conidium by septa, breaking in the middle to
release the conidium, a portion remaining attached to the
conidiogenous cell and the rest attached to the conidium.
Conidia arising singly, hyaline, smooth-walled, fusiform to
obclavate, extended apically into a long straight to slightly
arcuate rostrum to 30 μm long that tapers to c. 1 μm diam.,
with a portion of the separating cell adhering to the base,
(2–)3(–4)-septate, not to slightly constricted at the septa,
portion excluding the rostrum 28–35 × 5.5–7 μm, overall
length 35–65 μm.
Notes. This species is easily distinguished from the other
lichenicolous Trichoconis species by the mostly 3-septate
conidia. Hawksworth (1980) reported that colonies in the
type collection were conned to galls induced by a spe-
cies of Pyrenidium, while no Pyrenidium was present in the
specimen studied by Wagner (2013).
Ecology and hosts. On the thallus of Peltigera collina and
P. didactyla.
Trichoconis
by P. Diederich, W. von Brackel, U. Braun & D. L. Hawksworth
1 Conidia 0–1-septate, 12–34 × 7.5–11 μm, rostrum lacking in aseptate conidia; on corticolous hosts
............................................................................................................................................... Trichoconis physciicola (484)
1’ Conidia 2–4-septate, 35–65 × 5.5–7 μm, consistently with a distinct liform rostrum, to 30 μm long; on Peltigera
............................................................................................................................................... Trichoconis lichenicola (483)
Diederich, P., W. von Brackel, U. Braun & D. L. Hawksworth. 2024. Trichoconis. Flora of Lichenicolous Fungi 2: 483–486.
Abstract. The genus Trichoconis currently comprises two lichenicolous species: T. lichenicola, conned to Peltigera species, and T. physciicola,
known from various corticolous hosts. Trichoconis hafellneri is regarded as a synonym of T. physciicola.
Trichoconis lichenicola, Ireland, holotype (modied from Hawksworth
1980). Conidiophores, conidiogenous cells and conidia. Scale bars: 10 μm.

484
Diederich, Ertz & Braun – Flora of Lichenicolous Fungi – Vol. 2. Hyphomycetes – 2024
Trichoconis lichenicola, Germany, 2012. Conidia in ink-vinegar solu-
tion. Photo: W. G. Wagner. Scale bar: 10 μm.
Distribution. Europe (Germany; Ireland; UK: England).
References. Hawksworth 1980, Wagner 2013 [britishlichensoci-
ety.org.uk].
Trichoconis physciicola Brackel
Biblioth. Lichenol. 109: 380 (2014). Type: Germany, Mittel-
franken, Kreis Erlangen-Höchstadt, Geisberg SE Adelsdorf,
49°42’05”N, 10°54’48”E, 290 m, on Prunus spinosa, on Phy-
scia adscendens and P. tenella, 12 Nov. 2013, W. von Brackel
6710 (herb. von Brackel – holotype).
Syn. nov.: Trichoconis hafellneri U. Braun, Khodos., Dar-
mostuk & Diederich, Herzogia 29: 308 (2016). Type:
Ukraine, Kherson oblast’, Goloprystanskiy district, Chal-
baskaya area, village Promin’, near lake Shelemenske,
46°20’15”N, 32°49’7”E, 26 m, on Populus tremula, on
Xanthoria parietina (apothecia), 21 Nov. 2015, A. Kho-
dosovtsev & V. Darmostuk (KHER 9328 – holotype; BR,
KHER 3929 – isotypes).
Colonies euse-caespitose, loose to somewhat aggre-
gated, delicate, whitish. Mycelium immersed, of spar-
ingly branched, septate, hyaline, thin- and smooth-walled
hyphae, 2–5 μm wide. Conidiophores solitary to loosely
aggregated, arising from internal hyphae or immersed
swollen hyphal cells, erect, straight to somewhat curved,
unbranched, subcylindrical to mostly narrowed from base
to top, 20–60 × 3–8 μm (5–8 μm wide below and 3–5
μm wide above), 0–6-septate, hyaline, thin- and smooth-
walled, apex more or less obtuse. Conidiogenous cells in-
tegrated, terminal, polyblastic, hyaline, smooth-walled, c.
10–35 μm long, denticulate, with (1–)2–5 subcylindrical to
conical denticles, 1.5–4 × 1–1.5 μm, formed as separating
cells (i. e., denticles separated from the conidiogenous cell
by a thin, not very conspicuous septum), terminal, occa-
sionally lateral, scattered. Conidia solitary, hyaline, thin-
and smooth-walled, shape variable, subspherical, ovoid,
limoniform, broad navicular, pyriform to droplet-shaped,
base rounded or with an apiculum-like peg, occasionally
with remnants of the separating cell, 0–1-septate; aseptate
conidia (5–)12–15.5(–17) × (7.5–)8–9.5(–11) μm, apex
Trichoconis lichenicola
Trichoconis physciicola, Germany, holotype. Conidiophores on the thal-
lus of Physcia adscendens. Photo: W. von Brackel. Scale bar: 200 μm.
Trichoconis physciicola, Germany, holotype (modied from Brackel
2008). Conidiophores, conidiogenous cells and conidia (the right one
germinating). Scale bar: 10 μm.
Trichoconis physciicola

485
Trichoconis
rounded to apiculate, occasionally with a short apical exten-
sion (rostrum), 3–8 μm long; 1-septate conidia 22–34(–44)
× (7–)7.5–11 μm, lower cell ellipsoidal to lemon-shaped,
upper cell (rostrum) narrow and caudate, often collapsed.
Notes. This species is easily distinguished from Trichoc-
onis lichenicola by the 0–1-septate vs 2–4-septate co-
nidia and the often reduced rostrum. Trichoconis hafell-
neri has been described for specimens distinguished by
0–2-septate conidiophores (vs 0–6-septate), aseptate ma-
ture conidia (vs 0–1-septate) without a distinct rostrum
(vs frequently with a rostrum), and a dierent host se-
lection, Athallia and Xanthoria vs Physcia species. The
discovery of additional specimens on both Physcia spe-
cies and Xanthoria parietina has convinced us that the
Trichoconis physciicola, Ukraine, holotype of Trichoconis hafellneri (modied from Braun et al. 2016). A, Conidiophores on the apothecia of
Xanthoria parietina. B, Same, at a higher magnication. C, Conidiophores. D, Conidia. Scale bars: A = 200 μm, B = 100 μm, C–D = 10 μm.

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Diederich, Ertz & Braun – Flora of Lichenicolous Fungi – Vol. 2. Hyphomycetes – 2024
species is much more variable, suggesting a synonymy
of both taxa.
Ecology and hosts. On the thallus and/or apothecia of Ath-
allia pyracea, Melanohalea exasperata, Physcia adscen-
dens, P. leptalea, P. tenella and Xanthoria parietina.
Distribution. Europe (Austria; France; Germany; Ukraine).
Selected specimens examined. France: Puy-de-Dôme: Clermont-
Ferrand, S of Blanzat, les Sagnes, 45.8147°N, 3.0722°E, 510 m,
on Malus, on Physcia leptalea, 2023, Pinault (BR); Saint-Genès-
Champanelle, Nadaillat, 45.6879°N, 3.0333°E, 870 m, on Mel-
anohalea exasperata, 2023, Pinault (herb. Pinault, photos exam-
ined by us).
References. Brackel 2014, Braun et al. 2016 [Berger 2019, Brack-
el 2023, Eckstein et al. 2021, Stordeur et al. 2023].
Acknowledgements
P. Pinault (photos of Trichoconis physciicola), H. G. Wagner
(photo of T. lichenicola).
References
Berger, F. 2019. Über die Diversität lichenicoler Pilze in einem
Innviertler Hausgarten (Oberösterreich, Österreich). Herzo-
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Brackel, W. von 2014. Kommentierter Katalog der echtenbe-
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Brackel, W. von. 2023. Weitere Funde von echtenbewohnenden
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Braun, U. A., Y. Khodosovtsev, V. V. Darmostuk & P. Diederich.
2016. Trichoconis hafellneri sp. nov. on Athallia pyracea and
Xanthoria parietina, a generic discussion of Trichoconis and
keys to the species of this genus. Herzogia 29: 307–314.
Eckstein, J., W. von Brackel, J. Rettig, R. Cezanne & M. Eichler
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Trichoconis physciicola, Ukraine, holotype of Trichoconis hafellneri
(modied from Braun et al. 2016). Conidiophores, conidiogenous
cells and conidia. Scale bar: 10 μm.