Pyrenomycetes Species Page

Lasiosphaeria sorbina

Large clustered ascomata
Phragmospore
Lasiosphaeria sorbina (Nyl.) P. Karst., Mycoth. fenn. (Helsinki) 2: 164 (1873)
Sphaeria sorbina Nyl., Flora, Jena 45: 322 (1863) [1862]
Sordariomycetidae
Sordariales, Lasiosphaeriaceae
Figure from HOLOTYPE (H), GJS L555 Type Specimen: FINLAND. Helsingfors, on Sorbus aucuparia branch, 3/24/1863, Nylander (as Sphaeria sorbina Nyl., H). Material Examined: ECUADOR, EC-556 (NY). FINLAND, holotype (H). FRANCE, JF02053 (J. Fournier Herbarium). NETHERLANDS, as Sphaeria mutabilis, L. 10261 No. 10&11 (L). USA, LOUISIANA, GJS L555 (F); OHIO, Morgan s.n., as Lasiosphaeria ovina (NY).
Genbank Accession: AY587935 (ITS), AY587934 (ITS), AY436416 (LSU), AY436415 (LSU), AY60027 (Btub), AY600274 (Btub), AY600296 (RPB2), AY600295 (RPB2)
Complete Description
Ascomata ampulliform to ovoid, papillate, (240–) 320–460 µm diam, (280–) 370–600 µm high; numerous, scattered to gregarious, usually superficial, occasionally erumpent; tomentose, tomentum dull gray to brownish-gray or pale pinkish to orange, appressed, waxy, sometimes wearing away with age; neck conical, glabrous, sometimes with a distinct, grayish ring around black ostiole. – Ascomatal wall of textura angularis in surface view, in longitudinal section 3-layered, 48.5–76.5 µm thick, inner layer pseudoparenchymatous, 6.5–9.5 µm thick, composed of 3–5 layers of elongate to flattened, pale brown cells, middle layer pseudoparenchymatous, 12.5–22.5 µm thick, composed of 4–6 layers of angular, pale brown cells, outer layer prosenchymatous, 29.5–44.5 µm thick, composed of numerous layers of hyphae, hyphae 1.5–3.5 µm wide, hyaline to yellowish, septate, thin- to slightly thick-walled, becoming melanized and brown in outermost 3–6 layers. – Ascomatal apex with periphyses. – Centrum with yellow, pinkish, or rarely orange pigments which quickly diffuse in water. – Paraphyses filiform, 1.5–4.0 µm wide, hyaline, numerous, septate, unbranched, longer than asci. – Asci cylindro-clavate to clavate, 125–185 X 13–21.5 µm, medium-stipitate, stipe 26–52 X 4–8.5 µm, numerous, unitunicate, thin-walled, apex rounded to truncate; ring narrow, extremely shallow, refractive, indistinct; subapical globule absent, with 8, biseriate to triseriate ascospores. – Ascospores short cylindrical, ends rounded, 21.5–46 X 4.5–9 µm [33 ± 5.5 X 6.5 ± 1.0], straight to slightly curved, hyaline, aseptate to 1-septate, appendages absent; after liberation from the ascus up to 5-septate, occasionally producing phialides directly from the ascospore. Colonies slow-growing on WA and PDA, 15–28 mm diam and 15–27 mm diam in 21 d on WA and PDA, respectively, moderately slow-growing on CMA, 18–33 mm diam in 21 d, silky on all media, appressed, hyaline, becoming brownish gray to pastel red (7C2–8A5) on PDA; margin even, appressed, hyaline, not distinct; reverse same as the mat in all media; anamorph produced commonly over entire mat on WA, sparsely over entire mat on CMA and sparsely at the margin on PDA within 14 d. Hyphae largely undifferentiated, 1–3.5 µm wide, thin-walled, hyaline. – Conidiogenous cells phialides, produced laterally or terminally, delimited by a basal septum, monophialidic, obclavate to lageniform, 9–18 X 2–4 µm at widest part, hyaline, constricted below the collarette, 1–1.5 µm below collarette; collarette minute, slightly flaring, same color as phialide. – Conidia pyriform, truncate at base, 2.5–3.5 X 2–2.5 µm, hyaline, produced enteroblastically, aggregated in slimy heads; blastoconidia not produced. (from Miller & Huhndorf, 2004)
Occurrence
Found on dead, decorticated deciduous trees with remnants of bark in Europe, North America and South America.
Similar Taxa Comments
Lasiosphaeria sorbina possesses a broad geographic range and a wide range of tomentum and centrum colors. European specimens of L. sorbina possess a gray tomentum and a yellow or pinkish centrum, North American material possess a gray or bright orange tomentum and a yellow or orange centrum, and South American material possess a pale pinkish to pale orange tomentum and a yellow centrum. Lasiosphaeria cylindrospora also possesses a gray tomentum, but can be distinguished from L. sorbina by its hyaline centrum and longer ascospores (46–56 vs. 21.5–46). Lasiosphaeria capitata possesses a brown tomentum, yellow centrum, and similar size, allantoid ascospores (32-45 µm) and may be a synonym of L. sorbina.
Reference
Miller, A.N. and S.M. Huhndorf. 2004. A natural classification of Lasiosphaeria based on nuclear LSU rDNA sequences. Mycological Research 108(1): 26–34.