Peyritschiella Thaxt.

Santamaria, Sergi & Pedersen, Jan, 2021, Laboulbeniomycetes (Fungi, Ascomycota) of Denmark, European Journal of Taxonomy 781, pp. 1-425 : 283-284

Genus Peyritschiella Thaxt.

MB#3856

Proceedings of the American Academy of Arts and Sciences 25: 8 ( Thaxter 1890). –

Type species: P. curvata Thaxt.

Dichomyces Thaxt., Proceedings of the American Academy of Arts and Sciences 28: 183 ( Thaxter 1893) [MB#1516]

Rheophila Cépède & F.Picard, Compte rendu, Association Française pour l’Avancement des Sciences, 36 session, Reims 2: 783 ( Cépède & Picard 1907) [MB#4695]

Brief description

Monoecious. Receptacle laminate, multiseriate, consisting of a basal cell (I) and three superposed tiers of horizontally arranged cells which support compound flask-shaped antheridia, perithecia and unicellular appendages ( Fig. 68E ). Each tier of cells consists of a median or axial cell (II’, II”, and II’’’) which divides laterally by longitudinal septa giving rise to a variable number of laterally arranged cells. The axial cell of the upper tier supports what should be the terminal cell (III) which bears the primary appendage above a darkened and constricted primary septum ( Fig. 68E ). In the lower tier, the axial cell is mostly flanked at both sides by cells which divide by longitudinal septa into a variable number of cells. Perithecium with four cells in each vertical row of outer wall cells and sometimes bearing on the apex short finger-like expansions termed auricles.

Remarks

The genus consists of 49 species, of which 15 in Europe, six in Denmark. The most recently described species is P. heinemanniana ( De Kesel 1998) .

Thalli of Peyritschiella are very characteristic by the flattened, leaf-like and multiseriate receptacle. The primary appendage and the primary septum follow the axial cell in the upper tier (see Fig. 58 of Santamaria 1989: 293, although the position of cell III seems misunderstood in that figure). In the lower tier, the first two contiguous cells may also be once divided by horizontal septa (e.g., P. princeps , Fig. 69A–C , labelled with arrows in C; Santamaria 1989: 293), although not all the species show this character, for example P. oxyteli . To our knowledge, this feature, which has not been mentioned by any other author, may be a remarkable morphological character to be taken into account.

The genus Dichomyces ( Thaxter 1893) was separated early by differences in the symmetry of thalli, until Tavares (1985) decided with good judgment to unite them under the prioritary name of Peyritschiella . Symmetry or asymmetry of the receptacles are often altered by damage or by growth on unsuitable host body positions as, for example, the legs where fungi suffer the friction with environment. This genus is comparable to Rickia with whom it shares the subtribe Peyritschiellinae .

Key to the Danish species (partially following Majewski 1994b)

(Characters in the key are based on thalli in fair condition. In species of this genus any injury leads to strong variations in morphology)

1. Lower tier of cells laterally or entirely blackened, septa between cells obscured............................ 2

– Lower tier of cells not blackened or septa between cells clearly visible.......................................... 5

2. Perithecia usually with auricles ........................................................................................................ 3

– Perithecia without auricles (see P. hybrida for explanation) ............................................................ 4

3. Thallus slender and short, up to 60 µm broad and up to 160 µm long, with two perithecia ............... ................................................................................................................ P. furcifera (Thaxt.) I.I.Tav.

– Thallus bigger, up to 120 µm broad and up to 250 µm long, with four perithecia.............................. .................................................................................................................. P. vulgata (Thaxt.) I.I.Tav.

4. Thallus asymmetrical with only one perithecium on the upper tier, borne from one of the cells adnate to the axial cell.................................................................................................... P. nigrescens Thaxt.

– Thallus symmetrical with 2–6 perithecia.................................................. P. hybrida (Thaxt.) I.I.Tav.

5. Thallus symmetrical, with median and upper tiers of cells of similar width; with two perithecia. On Philonthus and allied genera (Col. Staphylinidae Staphylinini )............. P. princeps (Thaxt.) I.I.Tav.

– Thallus asymmetrical, with lower and middle tiers of cells primarily three-celled; with one brownish perithecium; appendages entirely tinged with brown. On Oxytelus and Anotylus Thomson, 1859 (Col. Staphylinidae Oxytelini )....................................................... P. oxyteli (Cépède & F.Picard) Santam.

Figures

Fig. 68. Peyritschiella spp. A–E. P. oxyteli (Cépède & F.Picard) Santam. comb. nov. A–D. Mature thalli. E. Immature thallus with labelling of cells I, II’, II”; II’’’, III, primary appendage (pa), and perithecium initial (per). – F–G. P. protea Thaxt. F. Mature thallus from Bledius in Spain. G. Mature thallus from type slide kept in FH. Scale bars: 50 µm. Photographs from slides ZMUC C-F-122472 (A–C) (neotype), ZMUC C-F-122702 (D), ZMUC C-F-122809 (E), BCB-SS2016 (F), FH2590 (G) (lectotype).

Fig. 58. Stigmatomyces spp. A–C. S. entomophilus (Peck) Thaxt. A–B. Mature thalli. C. Primary appendage in detail showing spinous process from the original spore apex (sx). – D–F. S. ephydrae L.Mercier & R.Poiss. D. Primary appendage in detail showing spinous process from the original spore apex (sx). E–F. Mature thalli. Scale bars: 50 µm. Photographs from slides ZMUC C-F-124020 (A–C), ZMUC C-F-124262 (D–F).

Fig. 69. Peyritschiella spp. A–C. P. princeps (Thaxt.) I.I.Tav. Mature thalli. In C arrows point to horizontal septa that divide the first two contiguous cells in the lower tier. – D. P. vulgata (Thaxt.) I.I.Tav. Mature thallus. Scale bars: 50 µm. Photographs from slides ZMUC C-F-122535 (A–B), ZMUC C-F-122536 (C), ZMUC C-F-123973 (D).