{{Short description|Genus of fungi}} {{Use dmy dates|date=July 2025}} {{Use Oxford spelling|date=July 2025}} {{Automatic taxobox | image = Hemigrapha nephromatis Wedin and Diederich (AM AK241945).jpg | image_caption = ''Hemigrapha nephromatis'' | taxon = Hemigrapha | authority = (Müll.Arg.) D.Hawksw. (1975) | type_species = ''Hemigrapha asteriscus'' | type_species_authority = (Müll.Arg.) R.Sant. ex D.Hawksw. (1975) | subdivision_ranks = Species | subdivision = | synonyms = *''Melanographa'' sect. ''Hemigrapha'' {{au|Müll.Arg. (1882)}} }}
'''''Hemigrapha''''' is a genus of fungi in the family Hemigraphaceae.<ref name="CoL"/> The genus was established in 1975 and currently includes nine recognised species. These fungi are parasites that grow on other lichens, producing distinctive flat, star-shaped or elongated black fruiting bodies on their host's surface.
==Description==
''Hemigrapha'' lacks its own thallus and instead parasitises other lichens. Its reproductive structures are flat, superficial fruiting bodies called thyriothecia. When young these appear black, round, star-shaped or elongate, and may branch or fuse together. Each thyriothecium is surrounded by a single layer of dark-brown, short rectangular cells arranged like spokes of a wheel; the covering breaks open irregularly, leaving the spore-bearing surface (hymenium) partly exposed while any true pore (ostiole) is often hard to discern. The hymenium does not stain blue in iodine tests. Threads known as {{lichengloss|paraphysoids}} weave through the asci; they branch only sparingly, sometimes fuse, and in mature fruiting bodies their tips separate and become slightly swollen and brown. Short, few-celled hairs ({{lichengloss|periphyses}}) arise from the inner wall.<ref name="Cannon et al. 2025"/>
The asci are thick-walled, double-layered ({{lichengloss|fissitunicate}}), club-shaped to almost spherical, and carry a distinct {{lichengloss|ocular chamber}} at the apex; they do not stain in iodine and usually contain between four and eight ascospores, though two-spored asci also occur. Ascospores develop one to three internal walls (septa), are clearly pinched at each septum, and change from colourless to pale brown as they mature. Initially smooth, they become finely {{lichengloss|granular}} or even warted in over-mature specimens; they possess no surrounding {{lichengloss|perispore}}. Asexual reproduction takes place in structures (pycnothyria) that are intermixed with, and macroscopically indistinguishable from, the thyriothecia. These lack conidiophores; instead, bottle-shaped conidiogenous cells emerge directly from the wall and produce two sizes of smooth, colourless, single-celled spores: narrowly ellipsoidal to rod-shaped microconidia and larger ellipsoidal macroconidia.<ref name="Cannon et al. 2025"/>
==Species== {{As of|2025|July}}, Species Fungorum (in the Catalogue of Life) accept nine species of ''Hemigrapha'':<ref name="CoL"/> *''Hemigrapha asteriscus'' {{au|(Müll.Arg.) R.Sant. ex D.Hawksw. (1975)}} *''Hemigrapha atlantica'' {{au|Diederich & Wedin (2000)}}<ref name="Diederich & Wedin 2000"/> *''Hemigrapha graphidicola'' {{au|Diederich & Common (2019)}}<ref name="Diederich & Common 2019"/> *''Hemigrapha nephromatis'' {{au|Wedin & Diederich (2000)}}<ref name="Diederich & Wedin 2000"/> *''Hemigrapha phaeospora'' {{au|Matzer & Lücking (1996)}}<ref name="Matzer 1996"/> *''Hemigrapha pilocarpacearum'' {{au|M.Cáceres & Lücking (2000)}}<ref name="Cáceres & Lücking 2000"/> *''Hemigrapha pseudocyphellariae'' {{au|Diederich & Wedin (2000)}}<ref name="Diederich & Wedin 2000"/> *''Hemigrapha strigulae'' {{au|Matzer (1996)}}<ref name="Matzer 1996"/> *''Hemigrapha tenellula'' {{au|(Müll.Arg.) R.Sant. ex Matzer (1996)}}<ref name="Matzer 1996"/>
==References== {{Reflist|refs=
<ref name="Cáceres & Lücking 2000">{{cite journal |last1=Cáceres |first1=M. |last2=Lücking |first2=R. |year=2000 |title=Three new species and one new combination of foliicolous lichens and lichenicolous fungi from the Atlantic rainforest in Pernambuco state, Brazil |journal=Nova Hedwigia |volume=70 |issue=1–2 |pages=217–226 |doi=10.1127/nova.hedwigia/70/2000/217 |bibcode=2000NovaH..70..217C }}</ref>
<ref name="Cannon et al. 2025">{{cite book |last1=Cannon |first1=P. |last2=Coppins |first2=B. |last3=Aptroot |first3=A. |last4=Sanderson |first4=N. |last5=Simkin |first5=J. |year=2025 |title=Miscellaneous lichens and lichenicolous fungi, including ''Aphanopsis'' and ''Steinia'' (Aphanopsidaceae), ''Arthrorhaphis'' (Arthrorhaphidaceae), ''Buelliella'', ''Hemigrapha'', ''Melaspileella'', ''Stictographa'' and ''Taeniolella'' (Asterinales, family unassigned), ''Phylloblastia'' (Chaetothyriales, family unassigned) ''Cystocoleus'' (Cystocoleaceae), ''Sclerococcum'' (Dactylosporaceae), ''Eiglera'' (Eigleraceae), ''Epigloea'' (Epigloeaceae), ''Euopsis'' (Harpidiaceae), ''Lichenothelia'' (Lichenotheliaceae), ''Lichinodium'' (Lichinodiaceae), ''Melaspilea'' (Melaspileaceae), ''Epithamnolia'' and ''Mniaecia'' (Mniaeciaceae), ''Lichenostigma'' (Phaeococcomycetaceae), ''Pycnora'' (Pycnoraceae), ''Racodium'' (Racodiaceae), ''Chicitaea'' and ''Loxospora'' (Sarrameanaceae), ''Schaereria'' (Schaereriaceae), ''Strangospora'' (Strangosporaceae), ''Botryolepraria'' and ''Stigmidium'' (Verrucariales, family unassigned), and ''Biatoridium'', ''Mycoglaena'', ''Orphniospora'', ''Piccolia'', ''Psammina'' and ''Wadeana'' (order and family unassigned) |series=Revisions of British and Irish Lichens |volume=57 |page=5}}</ref>
<ref name="CoL">{{Catalogue of Life |id=4V63 |title=''Hemigrapha'' |access-date=18 March 2024}}</ref>
<ref name="Diederich & Wedin 2000">{{cite journal |last1=Diederich |first1=P. |last2=Wedin |first2=M. |year=2000 |title=The species of ''Hemigrapha'' (lichenicolous Ascomycetes, Dothideales) on Peltigerales |journal=Nordic Journal of Botany |volume=20 |issue=2 |pages=203–214 |doi=10.1111/j.1756-1051.2000.tb01571.x |bibcode=2000NorJB..20..203D }}</ref>
<ref name="Diederich & Common 2019">{{cite journal |last1=Diederich |first1=Paul |last2=Common |first2=Ralph |last3=Braun |first3=Uwe |last4=Heuchert |first4=Bettina |last5=Millanes |first5=Ana |last6=Suija |first6=Ave |last7=Ertz |first7=Damien |year=2019 |title=Lichenicolous fungi from Florida growing on Graphidales |journal=Plant and Fungal Systematics |volume=64 |issue=2 |pages=249–282 |doi=10.2478/pfs-2019-0021 |doi-access=free}}</ref>
<ref name="Matzer 1996">{{cite book |last=Matzer |first=M. |year=1996 |title=Lichenicolous ascomycetes with fissitunicate asci on foliicolus lichens |series=Mycological Papers |volume=171 |page=107 |publisher=CABI |isbn=978-0851989372}}</ref>
}}
{{Taxonbar|from=Q5711606}}
Category:Dothideomycetes Category:Dothideomycetes genera Category:Lichenicolous fungi Category:Taxa named by Johannes Müller Argoviensis Category:Taxa described in 1882