(1) On rotten wood, Canterbury Prov., Kelsey's Bush, near Waimate, 17.X.1963, PDD 25073 (type) (DAOM 110267); (2) "295. Bactridium magnum C. Waitaki [scripsit Cooke; on rotten wood; New Zealand]" in Herb. K; (3) "smaller form [scr. Cooke]" is written on a small envelope included in the packet containing collection (2). Collections (2) and (3) above were included as "Waitaki (295)" in the list of collections cited by Cooke in his original description of Bactridium magnum (see above under B. clavatum). In collection (2) the 5-septate conidia measure 204-257 x 46-59 µm whereas in the packet labelled "smaller-form" (collection (3)) the 5-septate conidia are shorter, 165-191 x 45-59 µm. However, in view of the similarities in shape, septation, and width, it seems to me exceedingly doubtful that a separation into two taxa based on conidium length is merited. In any case the cotype collection "295" does not fit the original diagnosis and illustration of B. magnum Cooke and is quite unsuitable as lectotype of this name.

Sporodochia hemispherical, scattered or crowded, up to 800 µm in diameter, pale yellow to orange-brown. Mycelium immersed, composed of branched, septate, hyaline, smooth-walled hyphae which are here and there intricately and compactly interwoven to form a pseudostroma which is the base of a sporodochium. Conidiophores are crowded and arise from the basal cushion of the sporodochium; they are hyaline, septate, up to 250 µm long, much branched toward the base and sparingly branched above. Basal cells of conidiophores, which merge gradually with the hyphae comprising the basal cushion, are 10-12 µm wide, tapering gradually to 5-6 µm wide and then expanding gradually to 9.0-11.5 µm. wide at the point of attachment of the conidium. Conidiophore cells are 15-54 µm long but the terminal cell is frequently only 3.5-5.5 µm long, although it may be longer and up to 18 µm. Conidia are formed as blown-out ends at the apices of the conidiophores; they are ellipsoidal to rounded-rhomboidal, rounded at the distal end, truncate at the base, with the peripheral wall 3.5 µm thick. Conidia are predominantly 5-septate with the two central cells being the largest, sometimes slightly constricted at the central septum and rarely at the others; they measure 125-257 x 39-59 µm.

Sporodochia hemisphaerica, dispersa vel aggregate, ad 800 µm diem., pallide lutea vel aurantio-brunnea. Mycelium immersum, ex hyphis ramosis, septatis, anastomosantibus, hyalinis compositum. Pseudostromata ex hyphis dense intricatis formata. Conidiophora densa, ramosa, plus minusve cylindrica, hyaline, septata, ad 250 µm long., ad basim 10-12 µm cr., dein 5-6 µm attenuate, versus apicem 9.0-11.5 µm cr. inflate, cellulis 15-54 µm long., cellula apicali 3.5-5.5(-18) µm long. Conidia ellipsoidea vel rotundato-rhomboidea, crasso-tunicata (ad 3.5 µm), plerumque 5-septata, cellulis binis centralibus longioribus, aliquando ad septas constrictas; 125-257 x 39-59 µm.

Habitat: in ligno putrido.

Typus: in ligno putrido, New Zealand, Canterbury Province, Kelsey's Bush, prope Waimate, 17.X.1963, PDD 25073 (DAOM 110267).