Aschersonia calendulina Hywel-Jones & Mongkols., Mycol. Res. 113(6–7): 687 (2009)
Ascocalyx Naumov, Bolêz. Rast. 14: 138 (1926)
= Bothrodiscus Shear, Bull. Torrey bot. Club 34(6): 312 (1907)
Leotiomycetes, Leotiomycetidae, Helotiales, Godroniaceae
Saprobic or parasitic on the host plant. Sexual morph: see Groves (1936). Asexual morph: Conidiomata dark brownish to black or olivaceous black and fleshy-leathery when moist, sometimes arising on the same stroma as the apothecia, stromatic, pycnidial, solitary to gregarious, superficial, initially globose to subglobose, then opening circularly and becoming cupulate, broadly stipitate, multilocular, glabrous, with numerous locules at one level concealed by incurved margin. Ostiole absent, dehiscence by irregular splits of each locule wall. Conidiomatal wall composed of thick-walled, pale brown cells of textura porrecta to textura epidermoidea at the base, gradually merging with thick-walled, brownish cells of predominantly textura angularis above, becoming darker at the periphery. Conidiophores reduced to conidiogenous cells. Conidiogenous cells arising from inner layer cells of locular wall, hyaline, holoblastic, sympodial, cylindrical, indeterminate, smooth-walled, with 1–3 flattened, unthickened scars towards the apices. Conidia hyaline, lunate to falcate or cylindrical, with obtuse apex and truncate base, septate, smooth-walled (adapted from Groves 1936, 1968; Nag Raj 1977a; Sutton 1980).
Type species: Ascocalyx abietis Naumov, Morbi Plant. Script. Sect. Phytopath. Hort. Bot. Prince. USSR 14: 138 (1925) 
= Bothrodiscus pinicola Shear, Bull. Torrey bot. Club 34(6): 313 (1907)
Notes: In the original description, the host of Bothrodiscus pinicola was said to be Pinus virginiana, but it was later proved to be Abies balsamea (Pinaceae) (Groves 1936). A detailed list of synonyms of the type species was provided by Groves (1968a). The sexual morph of B. pinicola was linked to Ascocalyx abietis Naumov (type of Ascocalyx) on the basis of culture studies (Groves 1936). Groves (1968) provided more evidence on this connection, with two additional taxa of Ascocalyx associated with Bothrodiscus asexual morph. Johnston et al. (2014) and Wijayawardene et al. (2017b) reduced Bothrodiscus to a synonym of Ascocalyx, as the later sexual morph name was widely used. In the present study, we re-describe and re-illustrate the asexual morph of Ascocalyx. It is necessary to incorporate molecular studies to evaluate sexual and asexual morph connections of this genus.
Distribution: Canada, Finland, Japan, Pakistan, Spain, Sweden, Switzerland, Thailand, USA (Groves 1936; Sutton 1980; https://www.gbif.org/).
Ascocalyx abietis (asexual morph, redrawn from Nag Raj 1977a) a Vertical section of conidioma. b Enlarged view of locule. c Conidia. d Conidiophores, conidiogenous cells and developing conidia.
Li WJ, McKenZie EHC, Liu JK, Bhat DJ, Dai DQ, Caporesi E, Tian Q, Maharachcikumbura SSN, Luo ZL, Shang QJ, Zhang JF, Tangthirasunun N, Karunarathna SC, Xu JC, Hyde KD (2020) Taxonomy and phylogeny of hyaline-spored coelomycetes. Fungal Diversity 100: pages279–801.