Ne o t r o p i c a l Hy p o c r e l l a, Mo e l l e r i e l l a, a n d Sa m u e l s i a1 Effuse clade2 Globose clade3 Pulvinate clade A4 Pulvinate clade B<strong>Moelleriella</strong>Balansia henningsiana10 changes100/88/77100/98/6399/
Ch av e r r i e t a l.Morphological analyses <strong>and</strong> geographicaldistribution<strong>Moelleriella</strong>, <strong>Samuelsia</strong>, <strong>and</strong> Hypocrella/AschersoniaThe distributions of the species presented here are generally poorlyknown. Based on the specimens collected for this study, <strong>Moelleriella</strong>is most diverse <strong>and</strong> common in the Neotropics (22 known species),followed by Hypocrella (5 known species), <strong>and</strong> <strong>Samuelsia</strong> (5known species). <strong>Moelleriella</strong> <strong>and</strong> Hypocrella species are alsomore abundant that <strong>Samuelsia</strong>. Field collections <strong>and</strong> additionalspecimens from collaborators <strong>and</strong> herbaria yielded hundredsof specimens of <strong>Moelleriella</strong> <strong>and</strong> Hypocrella from many differentcountries. On the other h<strong>and</strong>, <strong>Samuelsia</strong> species are only knownfrom one collection each. <strong>Samuelsia</strong> rufobrunnea, S. chalalensis,<strong>and</strong> S. geonomis are known from Bolivia <strong>and</strong> Peru; S. sheikhii fromHonduras; <strong>and</strong> S. intermedia from Chile.Examination of multiple morphological characters showsthat segmentation of ascospores <strong>and</strong> conidial size <strong>and</strong> shapeare the main characters that distinguish <strong>Moelleriella</strong>, <strong>Samuelsia</strong>,<strong>and</strong> Hypocrella. All known species of <strong>Moelleriella</strong> have filiformmultiseptate ascospores that disarticulate at maturity inside theascus <strong>and</strong> fusiform conidia < 15 µm long. Hypocrella specieshave filiform to long-fusiform multiseptate ascospores that do notdisarticulate <strong>and</strong> fusiform conidia > 15 µm long. <strong>Samuelsia</strong> specieshave long-fusiform, non-disarticulating ascospores <strong>and</strong> smallallantoid conidia < 10 µm long. Another character common to mostspecies of Hypocrella <strong>and</strong> <strong>Samuelsia</strong> is a reddish colour reaction ofthe stroma when 3 % KOH is applied. However, H. citrina does notchange colour. All studied species of <strong>Moelleriella</strong> lack a reaction to 3% KOH. <strong>Moelleriella</strong> gaertneriana <strong>and</strong> M. cornuta release brownishpigments when 3 % KOH is added, but the tissue of the stromatadoes not change colour. Stromal anatomy is somewhat conservedin Hypocrella. The Hypocrella species examined have pulvinatestromata, with or without hypothalli. On the other h<strong>and</strong>, stromata in<strong>Moelleriella</strong> are highly variable: from flat or effuse with loose hyphaltissue (e.g. M. libera), to somewhat pulvinate (e.g. M. madidiensis)or knob-shaped (e.g. M. phyllogena, M. basicystis, M. umbospora,M. disjuncta), to large, globose <strong>and</strong> hard stromatal tissue (e.g. M.macrostroma, M. gaertneriana).Characters of the anamorph are somewhat useful indistinguishing between Hypocrella, <strong>Samuelsia</strong>, <strong>and</strong> <strong>Moelleriella</strong>.The three genera have pycnidial-acervular conidiomata, slenderflask-shaped to cylindrical phialides arranged in a compacthymenium, with or without paraphyses, brightly coloured <strong>and</strong> slimyconidial masses, <strong>and</strong> fusoid, unicellular conidia. Only conidialshape <strong>and</strong> size are useful characters.<strong>Moelleriella</strong> morphologyThe stromatal size of <strong>Moelleriella</strong> species treated in this studyranges from 0.5–30 mm diam. <strong>Moelleriella</strong> macrostroma, M.gaertneriana, <strong>and</strong> M. cornuta have large stromata that range from2–30 mm diam. The smallest stromata are those of M. umbospora,M. basicystis, M. turbinata, M. castanea, <strong>and</strong> M. colliculosa, whichrange between 0.5 <strong>and</strong> ca. 2 mm in diam. The size of the stromais generally correlated with the number of perithecia or pycnidiaper stroma. The colours of the stromata of the species studiedare in shades of white, yellow, orange, brown, or black. White<strong>and</strong> orange are the most common colours. A few species, i.e. M.cornuta, M. turbinata, M. palmae, M. guaranitica, M. globosa, <strong>and</strong>M. castanea, have brown to almost black stromata; these speciesare phylogenetically related in the Globose clade (Figs 1–2).Most of the examined species in the Effuse clade have stromatain shades of white or orange. The shapes of the stromata arehighly variable. They can range from effuse or flat, to somewhatpulvinate, globose, cerebriform, tubular, conical, or knob-like.<strong>Moelleriella</strong> libera, M. ochracea, M. sloaneae, <strong>and</strong> M. evansii haveeffuse or thin, pulvinate stromata. <strong>Moelleriella</strong> zhongdongii, M.madidiensis, M. rhombispora, M. guaranitica, M. castanea, <strong>and</strong>M. epiphylla, have pulvinate to convex stromata. The surface ofthe stroma can be shiny or dull/matt, opaque, glabrous or scurfy,<strong>and</strong> tomentose or roughened. Most species of <strong>Moelleriella</strong> have astromatal surface that is opaque <strong>and</strong> pruinose; however, there aremany exceptions. <strong>Moelleriella</strong> libera, M. evansii, M. zhongdongii,M. madidiensis, M. ochracea, M. rhombispora, M. sloaneae, <strong>and</strong>some forms of M. basicystis, M. disjuncta, M. phyllogena, <strong>and</strong> M.umbospora, have tomentose stroma surfaces. Teleomorph stromataof M. basicystis, M. disjuncta, M. phyllogena, <strong>and</strong> M. umbospora,<strong>and</strong> stromata of M. macrostroma, M. gaertneriana, M. boliviensis,M. turbinata, M. epiphylla, M. cornuta, M. palmae, M. globosa, M.guaranitica, M. castanea, <strong>and</strong> M. colliculosa have almost glabroussurfaces. Stromata of M. macrostroma, M. gaertneriana, <strong>and</strong> M.cornuta, have somewhat shiny stromata. Hypothalli are presentin some species, except M. epiphylla, M. turbinata, M. boliviensis,M. macrostroma, <strong>and</strong> M. gaertneriana, M. castanea, M. colliculosa,M. globosa, <strong>and</strong> M. guaranitica. There is no reaction to 3 % KOHon the tissue of the stromata; only M. gaertneriana <strong>and</strong> M. cornutarelease brownish pigments when KOH is added. The tissuestructure of the stroma surface is highly conserved among theexamined species. All species studied have the tissue type referredto as textura intricata or epidermoidea. Some differences are foundin the thickness of the cell walls. Darkly pigmented hard stromataare composed of hyphae with thick cell walls (ca. 2–6 µm). Lightlypigmented stromata with loose hyphal tissues have thin-walledhyphae (ca. 1 µm). The inner tissue below the outermost layerof the stroma is generally of textura oblita, intricata, epidermoideaor a condition intergrading between these tissue types.Perithecia in some species of <strong>Moelleriella</strong> can be formed inwell-separated or gregarious tubercles, or they can be completelyembedded in the stroma. <strong>Moelleriella</strong> libera, M. ochracea, M.rhombispora, M. zhongdongii, M. evansii, <strong>and</strong> M. sloaneaeform perithecial tubercles. When the stroma contains perithecia<strong>and</strong> pycnidia, the perithecia are either towards the edges of thestroma or scattered, with pycnidia either clustered in the centre orinterspersed among the perithecia, respectively. The ostioles canrange in colour from yellow to orange yellow, to reddish brown orbrownish yellow. In longitudinal section, perithecia are generallyelongated to subglobose, sometimes globose, with walls composedof 3–4 layers of highly compacted, thin-walled cells.The asci are cylindrical <strong>and</strong> sometimes swollen in the middlewhen ascospores have disarticulated <strong>and</strong> accumulated towardsthe middle. Generally the ascus cap is thickened (ca. 2–5 µm)<strong>and</strong> capitate. <strong>Moelleriella</strong> boliviensis, M. epiphylla, M. globosa,M. guaranitica, M. colliculosa, <strong>and</strong> M. castanea have thin ascustips (< ca. 1.5 µm). Because the multiseptate filiform ascosporesdisarticulate at the septum inside the ascus upon mounting, itis difficult to know exactly the length of intact ascospores. Thepart-ascospores are always hyaline <strong>and</strong> smooth. They canvary in shape, from cylindrical, to fusoid, ventricose, or almostovoid. <strong>Moelleriella</strong> basicystis, M. phyllogena, M. umbospora,<strong>and</strong> M. disjuncta have a swollen protuberance on one side ofthe part-spore. In M. rhombispora, the part-spores have similarprotuberances in the middle (i.e. ventricose shape). For themost part, the species studied have part-spores ca. 9–14 µm16
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