Pyrenomycetes Species Page

Acanthostigma multiseptatum

Small separate ascomata
phragmospore
Promputtha & A.N. Mill.

Dothideomycetes
Tubeufiaceae
Figure from ANM475 (ILLS 59354, HOLOTYPE) Type Specimen: ILLS 59354 (ANM475); Paratype = ILLS 59355 (ANM665)
Genbank Accession: GQ856145 (ITS), GQ850492 (LSU)
Complete Description
Ascomata superficial, scattered or gregarious, globose to subglobose, 130–380 µm diam, 130–380 µm high, shiny black when dry, densely setose, non-collapsing. Setae 1-celled or septate, thick-walled, brown to dark brown, straight to slightly curved, with acute tip, 45–85(–100) µm long, 4–6.5 µm wide in the middle. Ascomatal wall single-layered in longitudinal section, composed of 3–5 rows of brown, thick-walled, polygonal to angular or flattened cells. Pseudoparaphyses numerous among asci, branched, hyaline. Asci bitunicate, cylindrical-clavate to clavate, broadly rounded and thickened at the apex, short-stipitate, 8-spored, (90–)105–145 × 20–25 µm [120 × 22.5 ?m, n = 20]. Ascospores fusiform, straight or slightly curved, tapering and narrowly rounded at both ends, ends symmetrical, 14–18 septate, not constricted at the septa, hyaline, 60–90 × 5–7.5 µm [72 × 6.5 ?m, n = 146].
Occurrence
This species is commonly found throughout the Great Smoky Mountains National Park where it occurs scattered to gregarious on decorticated wood in mixed coniferous-deciduous forests.
Similar Taxa Comments
Acanthostigma multiseptatum possesses ascospores with the greatest number of septa in the genus. It is most similar to A. minutum (Fuckel) Sacc., but differs in having longer asci and longer ascospores with more septa.
Reference
Promputtha & Miller 2009, Mycologia 102(3): 574–587.