Metacapnodium ericophilum D. Hawksw. & S. Hughes

Metacapnodium ericophilum (Link) D. Hawksw. & S. Hughes Fig. 8 Specimen examined. Spain • Comunidad de Madrid: Sierra de Guadarrama, Parque Regional de la Cuenca Alta del Manzanares, La Pedriza de Manzanares, on Erica arborea L., 22 Nov. 2004, D. L. Hawksworth, DAOM 234182 a. GenBank accession numbers. ITS, OR 532934; LSU, PP 140683. Description. Subicula blackish, superficial, developing confluent thick and cracked cushions extending over host branches. Mycelia of doliiform and moniliform, brown to dark brown hyphae. Hyphae branching, straight, surface verrucose, tapering towards their tips. Hyphal cells to ~ 27 µm in diameter when mature, 5 µm in diameter at tip. Sexual form. Ascomata scattered to crowded, dark brown to black, globose, some subglobose, semi – immersed in subicula, 90–180 (– 200) × 90–180 µm, bearing moniliform appendages. No mature asci or ascospores observed. Asexual forms. Capnocybe – Synnemata up to 800 µm high, sparsely distributed throughout the subicula, their basal hyphae of ellipsoidal to globose cells, stipes 350–600 × 50–150 µm. Stipes of compact, fasciculate hyphae with cylindrical to ellipsoidal cells tapering to 6 µm towards the apex. Heads (capitula) of synnemata up to 300 µm wide. Terminal conidiogenous cells cylindrical, 10–16 × 5.5–7 µm, producing successive conidia blastically at their tips. Conidia fusiform, (2 –) 3 – septate, dark brown, (25) – 33 – (39) + / – 2.7 × (8) – 9.2 – (12) + / – 0.7 µm, Q = 3.6. Capnophialophora – Phialides light brown to brown, subspherical venters 5–6 µm wide, near-cylindrical collarettes up to 4 µm by 2–4 µm. No phialidic conidia observed. Hosts and distribution. Hawksworth and Boluda (2020) reported the species from Spain and Portugal, commonly on Erica arborea, also on Erica australis, and perhaps present on other species of Erica. Notes. Phylogenetically, this species appears as sister to M. spongiosum in the ITS tree with 84–85 % bootstrap support (Fig. 2) and ITS sequences of the two species only differ by about 2 %. Both species produce capnocybe forms with similar, penicillate conidiogenous cells and their conidia are of similar shape, size and septation. Phialides in both species are somewhat unusual for Metacapnodium in that collarettes are subcylindrical rather than funnel-shaped. The two species differ in known geographical and host ranges: M. ericophilum forms dense subicula covering branches of Erica in Spain and Portugal, while M. spongiosum forms dense subicula covering branches of Calocedrus decurrens from California (Hughes 1966), and from Oregon, based on our re-identification of specimen OSC 135428 (Table 1). Hughes (1976) recognized the similarity of these two species but considered Antennaria ericophila Link, the basionym of M. ericophilum, to be a nomen dubium due to lack of clarity about its application. Hawksworth and Boluda (2020) resolved the application of the name, epitypified and lectotypified M. ericophilum, and sequenced the ITS region of DAOM 234182, the same specimen we used for sequencing ITS and ef 1 - a gene regions. M. ericophilum was abundant on Erica arborea but not on nearby junipers, and Hawksworth and Boluda suggested this may indicate host specificity but alternatively, it could reflect a fungal requirement for honeydew from particular scale insects, and only indirectly for the plant genus.