Auriculariales » Auriculariales genera incertae sedis » Ovipoculum

Ovipoculum album

Ovipoculum album Zhu L. Yang & R. Kirschner 2010, in Kirschner et al., Fungal Diversity, 43, 55-65 (2010)

Diagnosis: Conidiomata gelatinous when wet, white or somewhat translucent, cupulate, almost sessile, laterally attached to the substratum, 2–6 mm wide, 1.5–5 mm long and 1–3 mm thick. Root-like structures extending from the base into the substratum not found. Upper surface of the conidiomata slightly concave, in many cases wider than long when seen from above, composed of uniform, gelatinised, loosely interwoven hyphae being 2–2.5 μm wide, sometimes slightly swollen at the septa, with clamps at the septa, clamps often with a posterior appendage that in some cases is delimited by a retraction septum. Bulbils formed on the upper side in the shallow depression of the conidioma, inconspicuous when wet, more conspicuously raised when the conidioma has become a horny layer during drying, initials embedded in the upper half of the conidioma, formed of terminal and lateral branches by dense and repeated branching and septation of normal hyphae, clamps becoming indistinct from hyphal cells, neighbouring branches sometimes uniting, hyphae of the ball-like initials first not wider than the other hyphae, then gradually by swelling of the hyphal cells forming homogeneous balls of closely appressed isodiametrical or irregular cells, due to swelling and pressure from more basal, developing new bulbil initials gradually moved to the upper surface and eventually detached from the supporting hyphae. Bulbils hyaline or white, easily detached from the conidioma, almost subglobose, (75–) 83–117(–150) μm diam., sometimes ovoidal or ellipsoidal, surface inconspicuously ornamented with sparse conical projections of outermost cells and sometimes with hyphal fragments, in the mature stage being easily separable into thin-walled, smooth cells measuring 3–26× 6–22 μm.

Index Fungorum Number: IF516042

Figure 1. Habitus of conidiomata of Ovipoculum album. a Photograph of conidiomata in nature (HKAS 57058). b Schematic sketch of longitudinal section through conidioma indicating the distribution of bulbils and bulbil initials (HKAS 48722). Scale bar=100 μm

Figure 2. Clamp connections of vegetative hyphae of Ovipoculum album (HKAS 48722). Scale bar=10 μm

Figure 3. Part of a longitudinal section through a conidioma of Ovipoculum album (HKAS 48722) showing the distribution of bulbils and bulbil initials in the upper surface stained with phloxine. Scale bar=100 μm

Figure 4 Bulbils of Ovipoculum album (HKAS 48722). a Hypha with lateral initiation of bulbil development. b Bulbil initial at more progressed stage of development than in a. c Outlines of mature bulbils, cellular composition only indicated in the upper left one. d Detail of cellular composition of mature bulbil in slightly squashed mounting. e Separated cells of mature bulbil. f, g Scanning electron micrographs of mature bulbils on the upper surface of a conidioma. Scale bars: A, B= 10 μm, C=50 μm, D, E=20 μm, F=100 μm, G=30 μm

Figure 5. One of the five most parsimonious trees resulted from a phylogenetic analysis of partial nuclear large subunit ribosomal DNA sequences of Ovipoculum album and selected taxa of Basidiomycota. Numbers above branches are bootstrap values (≥50%). 1 Sequences obtained in this study; 2 sequence by Begerow et al. (1997); 3 sequence by Zhang et al. (2004); 4 sequence by Kirschner et al. (2001); 5 sequence by Kirschner & Chen (2004); 6 sequence by Weiß et al. (1998); 7 sequence by Kirschner & Yang (2005). The remaining sequences were provided by Weiß & Oberwinkler (2001).