Diaporthomycetidae families incertae sedis » Trichosphaeriaceae » Brachysporium

Brachysporium obovatum

Brachysporium obovatum (Berk.) Sacc.
≡Helmisporium obovatum Berk. (1841) [MB#492192]

 

Sexual morph: Perithecia nearly superficial with base slightly immersed, solitary or in small groups, globose to subglobose, conical around the ostiole, papillate, (150–) 170–210 µm diam., (160–)210–220 µm high, dark brown to nearly black, glabrous. Perithecial wall 22.0–26.0(–30.0) µm thick, leathery to fragile, consisting of two regions. Paraphyses persistent, branching, hyaline, septate, 3.0–5.0 µm wide near the base, tapering to 1.5–2.0 mm, longer than the asci. Asci cylindrical-fusiform, (72.0–)85.0–118.0(–128.0) µm long (x̄ =  91.7 ± 1.1 µm) in pars sporifera, (7.5–)8.0–10.0 (–11.0) µm wide (x̄ = 8.7 ± 0.1 µm), with long, slender stipe, (12.0–)20.0–35.0(–44.0) µm long (x̄ = 5 27.3 ±0.8 µm), with age disintegrating externally along the vertical axis and becoming longer up to 52.0–66.0 µm, L/W 13.5:1, broadly rounded to truncate at the apex, with distinct refractive apical annulus, ca. 3.0 µm diam, 2.0 µm high, containing eight obliquely uni- or biseriate spores. Ascospores ellipsoidal to fusiform to oblong-lemon-shaped, straight or inequilateral, (14.0–) 15.0–18.0(–20.0) µm long (x̄ = 16.0 ± 0.1 µm), (4.0–) 5.0–6.0(–7.0) µm wide (x̄ = 5.7 ± 0.04 µm), at first 1-celled, with a median septum forming at maturity, not constricted at the septum, smooth-walled. Asexual morph: Colonies on the natural substrate effuse dark brown, hairy, conidiophores interspersed among the perithecia. Conidiophores mononematous, macronematous, solitary, erect, straight or slightly flexuous, cylindrical, unbranched, dark brown, paler toward the apex, 1–7-septate, darker brown at the septa, 140–420 µm long, 6.5–8.5 µm wide at the base, 5.0–7.0 µm wide in the middle, tapering to 3.0–4.0 µm. Conidiogenous cells integrated, terminal, sympodially proliferating, polyblastic, denticulate, hyaline. Conidia ellipsoidal, 17.0–23.0 µm long (x̄ = 18.9 ± 0.7 µm), 8.0–11.0 µm wide (x̄  = 9.8 ± 0.2 µm), 3-septate, not constricted or gently constricted at the septa, versicolorous, two middle cells brown, polar cells hyaline to subhyaline to very pale brown, smooth-walled; conidia borne on short subhyaline pedicels singly or in groups at the apex of conidiophore. (Réblová & Seifert 2004)

Characteristics in culture: Colonies after 21 d on Blakeslee’s MEA at room temperature 1–2 mm diam, convex, sterile, with moderately dense somewhat radiating aerial mycelium, grayish brown in mass, the reverse dark brown to black, the margin discrete to slightly gnawed.

 

Distribution: USA, Florida, on submerged substrate in lentic habitat in Ocala National Forest (Raja et al. 2009).

Notes: Sequence data is not available.

 

References

Réblová M, Seifert KA (2004) Cryptadelphia (Trichosphaeriales), a new genus for holomorphs with Brachysporium anamorphs and clarification of the taxonomic status of Wallrothiella. Mycologia 96:343–367.

Luo ZL, Hyde KD, Liu JK, Maharachchikumbura SSN et al. 2019 – Freshwater Sordariomycetes. Fungal Diversity 99, 451–660.

 

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