Cucurbitaria laburni  

Anamorph: Camarosporium sp. fide Mirza (1968); probably synonymous with C. laburni (Westend.) Sacc. Conidiomata 180-250 µm diam, ± globose, clustered on the basal mycelium, black with a superficial reddish brown scurfy layer, ± smooth, thick-walled; composed of an outer layer of dark brown thick-walled cells intermediate between textura angularis and globulosa merging into an inner layer of thin-walled pale brown angular cells. Conidiophores absent, the conidiogenous cells arising directly from a layer of thin-walled hyaline textura angularis. Conidiogenous cells 9-12 x 7-10 µm, ampulliform, proliferating percurrently with distinct annellations, collarettes inconspicuous. Conidia 17-26 x 10-12 x 7.5-10.5 µm, cylindric-ellipsoidal, rarely ovoid, laterally flattened, the apices widely rounded, with 3-4(-6) transverse septa and a single irregular longitudinal septum which often does not divide all the transverse segments, not constricted, reddish brown, without a mucous sheath.

Teleomorph: Stromata subperidermal, composed of intertwined dark reddish brown thick-walled hyphae, bearing ascostromata strongly erumpent in clusters of up to 80, to ca 5 x 4 mm in overall dimensions, sometimes elongated transversely, the outer bark layers peeling back around the emergent stroma. Ascomata 350-750 µm diam and up to 1200 µm tall, turbinate, usually long-stalked, the apical region flattened, usually with a deeply sunken ostiole, matt black, scurfy or slightly verrucose. Peridium composed of an outer layer to 70 µm thick of dark brown thick-walled textura globulosa merging into a wide inner layer composed of similarly shaped pale brown thinner-walled cells, the locules lined with thick-walled flattened glassy hyaline cells. Interascal tissue composed of copious fairly thick-walled septate pseudoparaphyses to ca 3 µm diam. Asci 210-240 x 12-14 µm, cylindrical, usually short-stalked, thick-walled and fissitunicate, the apex rounded with a distinct invagination in the inner wall, usually 8-spored but a small proportion 4- or 6-spored. Ascospores 25-33 x 10.5-12 µm, rather variable in shape but frequently cylindric-fusiform, the apices ranging from truncate to acute, reddish brown, mucous sheath absent, constricted at the ± median primary septum, with 4-6 further transverse septa and usually a single longitudinal septum, the arrangement irregular.

Material on hosts other than Laburnum such as Cytisus may belong to other members of the species complex, e.g. C. spartii.