Rhachomyces pilosellus (C.P.Robin) Thaxt.

MB#192158

Fig. 18C–D

Proceedings of the American Academy of Arts and Sciences 30: 467 (Thaxter 1895). – Basionym: Laboulbenia pilosella C.P.Robin, Traité du Microscope: 912 (Robin 1871) [MB#566983]. –

Type: [Not designated] “ On Lathrobium from an unknown locality in France ”. [According to Santamaria et al. 1991, the type is an “ iconotype ”, i.e., the illustration given by Robin, which agrees with the ICNAFP – International Code of Nomenclature for Algae, Fungi and Plants (Turland et al. 2018)]

Acanthomyces brevipes Thaxt. (Thaxter 1893: 177) [MB#581132]. – Rhachomyces brevipes (Thaxt.) Saccardo (Saccardo 1895: 454) [MB#188964]

Diagnostic features

Main axis short, consisting of 4–5 cells, continuing to a 3–4 celled lateral branch. A blackish diagonal strip is seen traversing from cell I to cell II (Fig. 18C–D, arrows). Appendages “a” and “b” darkened, very elongated, yet coiled if undamaged (Fig. 18C). Type “c” appendages clustered below the perithecium. Perithecium very large, longer than main receptacle axis. [Detailed descriptions: Thaxter 1896; Majewski 1994b; De Kesel 2002]

Distribution and hosts

Grows on Lathrobium (Col. Staphylinidae Paederinae). An uncommon species only reported from France (type), Germany (Thaxter 1893), Poland, Ukraine (Siemaszko & Siemaszko 1932), Belgium (Collart 1945), Italy (Rossi 1975), and Hungary (Bánhegyi et al. 1985).

Collections examined from Denmark

On Lathrobium fulvipenne (Gravenhorst, 1806) (Col. Staphylinidae Paederinae)

DENMARK – Fyn (F) • Gyldenstens inddaemmede Strand; 55°34.447′ N, 10°7.211′ E; NG75; 2 Apr. 2014; JP 687; JP det.; ZMUC C-F-123175 . – Sydsjaelland (SZ) • Østerskov ved Langebaek; 54°59.572′ N, 12°6.715′ E; UA19; 3 Jan. 2019; JP 1300; JP det.; ZMUC C-F-123833 .

Remarks

First record from Denmark. This is one of the earliest described species of Laboulbeniales .