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Page number:608 
Description type:Non-original description 
Description:Botryosphaeria stevensii Shoemaker, Can. J. Bot. 42: 1299. 1964. FIGS. 19-38
=Physalospora mutila N.E Stevens, Mycologia 28:333. 1936, as Physalospora mutila (Fries) N. E. Stevens comb. nov.
Anamorph: Diplodia mutila Fries in Montagne, Ann. Sci. nat., sér. 2, 1:302 (1834). = Sphaeria mutila Fries, Syst. Mycol. 2:424-425. 1823.
Synonyms of D. mutila are given by Stevens (1933). The description is based on BPI 599153 (P. mutila) and K(M)99664 (D. mutila).
Ascomata unilocular, solitary or clustered, immersed, partially erumpent when mature, globose, up to 300 µm diam, dark brown to black, thick-walled, wall composed of outer layers of thick-walled, dark brown textura angularis, inner layers of thin-walled, hyaline textura angularis. Ostiole central, circular, papillate, periphysate. Pseudoparaphyses hyaline, branched, septate, 2-3 µm wide. Asci clavate, stipitate, bitunicate, 100-160 x 14-22 µm (including stipe), containing eight, biseriate ascospores. Asco-spores (24.8-)30.8-32.1(-36.2) x (9.5-)11.2-11.7 (-13.4) µm (mean ± S.D. of 50 ascospores = 31.5 ± 2.3 x 11.4 ± 0.9 µm) with length width ratio of 2.8 ± 0.3, fusiform, widest in the middle, both ends obtuse, hyaline, thin-walled, smooth, aseptate, rarely becoming light brown and 1- or 2-septate with age.
Conidiomata solitary or aggregated in clusters of up to five or more, immersed, partially erumpent when mature, dark brown to black, more or less globose, up to 600 µm diam, wall composed of three layers, an outer of dark brown, thick-walled textura angularis, a middle layer of dark brown thin-walled cells, an inner layer of thin-walled hyaline cells. Ostiole central, circular, papillate. Conidiophores absent. Conidiogenous cells (11-)12-15 x 4-5 µm, holoblastic, discrete, cylindrical, hyaline, smooth, indeterminate, proliferating at the same level giving rise to periclinal thickenings, or proliferating percurrently to form one or two indistinct annelations. Conidia hyaline, aseptate, smooth, thick-walled, oblong to ovoid, straight, both ends broadly rounded, (23.5-)25.1-25.7(-27.4) x (12.4-)13.2-13.5(-14.3) µm, mean and standard deviation of 50 conidia = 25.4 ± 1.0 x 13.4 ± 0.5 µm, length/width ratio (average of 50 conidia) = 1.9 ± 0.1, rarely becoming pale brown and septate with age.
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