Crittendenia Diederich, Millanes, M. Westb., Etayo, J.C. Zamora & Wedin gen. nov.

MycoBank number: MB 835604; Index Fungorum number: IF 835604; Facesoffungi number: FoF;

Differs from Chionosphaera by the presence of basidial clamps.

Type species: Crittendenia coppinsii (P. Roberts) Diederich, M. Westb., Millanes & Wedin. (Fig. 3)

Basidiomata developing on lichens, stipitate-capitate, synnemata- like, fleshy waxy, pale, slightly translucent; capitulum slightly to strongly differentiated and enlarged. Stipe composed of parallel, rarely branched hyphae with few septa; hyphidia and haustorial branches unknown. Basidia apical, tubular, aseptate, thin-walled, with basal clamps, when immature apically rounded, when mature with 4–7 apical, short, inconspicuous sterigmata, collapsing after spore detachment. Basidiospores hyaline, aseptate, ellipsoid to fusiform, with a small, often indistinct, basal apiculus, not forcibly discharged, often liberating together as a cluster of 4–7 spores. Basidiospores probably capable of germination by budding. Asexual conidial stage unknown.

Etymology: We are very happy to dedicate the new genus to our friend and colleague Peter Crittenden to endorse the importance of his lichenological career. This is not only to recognize his impressive and highly valuable work as a lichen symbiosis researcher, but above all to acknowledge his outstanding contributions as Senior Editor of The Lichenologist over the past 20 years.

Ecology: Lichenicolous, associated with a large variety of lichens belonging to different phylogenetic lineages.

Fig. 3. Diversity of Crittendenia species. A, immature basidiomata on Melanohalea exasperatula. B, mature basidiomata on Melanelixia glabratula. C, basidiomata on Hypotrachyna laevigata. D, slender basidiomata on Fellhanera bouteillei. E, entire basidioma (in Congo red). F, basidia with basal clamps (arrows), some with incon- spicuous sterigmata and/or young basidiospores (arrow heads) (in Melzer’s reagent). G & H, basidia with sterigmata and basidiospores (in Congo red). I, basidium development: immature basidium (left), mature basidium with basidiospores (middle), old basidium (right) (in phloxine B). J, mature basidium with basidiospores (in Melzer’s reagent). K, cystidium-like structure of unknown function (in Melzer’s reagent). L, basidiospores (in Melzer). M, clusters of basidiospores separated from basidia. A, B, E, F, I–L, Crittendenia coppinsii (A & F, van den Boom 54983; B, E, I–L, Groner 714); C, Crittendenia sp. (Diederich 4913); D, Crittendenia sp. (van den Boom 56901); G, H & M, Crittendenia sp. on Bacidia (Kalb 26946). Scales: A–D = 200 μm; E = 50 μm; F= 10 μm; G–M= 5 μm.

Species