Lophodermium oxycocci (Fries:Fries) Karsten, Mycologia Fennica 2: 244 (1873).
= Hysterium oxycoccos Fries:Fries, Systema mycologicum 2: 588 (1823).
= Hypoderma oxycocci (Fries:Fries) Kunze, Revisio Generum Plantarum 3(3): 487 (1898).
= Lophodermium oxycocci (Fries:Fries) Karsten var. hypophyllum Dearn. & House. [fide Eriksson, Symb. Bot. Ups. 19:42 (1970).]

ANAMORPH Leptostroma oxycocci Hilitzer, Ved. Spisy csl. Akad. zemed. 3: 83 (1929). - but see notes below.

HOST Vaccinium (Ericaceae)

DISTRIBUTION N America, Europe

TYPE UPS, lectotype - Fries, Scler. Suec. 169 [fide Eriksson, Symb. Bot. Ups. 19:42 (1970)]

SPECIMENS EXAMINED USA, Washington, Long Beach, on Vaccinium macrocarpum, coll. C.L.Shear, 17.ix.1913 (BPI, as L. hypophyllum).
USA, Washington, Spring Bog, on Vaccinium macrocarpon, coll. N.E.Stevens, iv.1920 (BPI, as L. hypophyllum).
USA, Oregon, Elatsop, on Vaccinium macrocarpon, coll. H.F.Bain, v.1925 (BPI, as L. hypophyllum).
USA, Minnesota, Meadowlands, on Vaccinium oxycoccus, coll. C.L.Shear, 21.viii.1914 (BPI, as L. hypophyllum).
USA, New York, near Swan Lake, on Vaccinium oxycoccus, coll. C.L.Shear, 6.viii.1927 (BPI, as L. hypophyllum).

REFERENCES Eriksson, Symb. Bot. Ups. 19:42 (1970), on leaves, notes that Shear, U. S. Dept. Agr. Tech. Bull. 258 (1931), was confused, the samples he considered L. oxycocci were in fact L. melaleucum. Eriksson has studies types of both L. oxycocci and L. hypophyllum (NYS) and found them conspecific. Rehm, Rabenh. Krypt.-Fl. ed.2, 1(3): 39-40, 1247 (1887). Hilitzer 1929:82-84. Zeller, Mycologia 26: 293 (1934) considered this sp. characterised by always being on upper leaf surface, and by the long ascospores.

EXSICCATI Fries Scl. Suec. 169; Rehm Ascom. 1065; Jaap F. S. E. 369.

NOTES Hilitzer cites Scl. Suec 169 and Rehm Ascom. 1065 under this name. However, as shown by Eriksson (1970) Rehm 1065 is in fact L. melaleucum. Thus Hilitzer's description of an anamorph for this species MAY be incorrect - certainly one is not evident on the Eriksson collections ex UPS, but not so clearcut for the Fries specimen, in which, on some leaves at least, dark brown to almost black pustulate structures resembling pycnidia of Lophodermium are present.
Appears that 2 fungi may be present on Fries Scl. Suec. 169. One, with mature ascomata has pale brown walls with dark line along outside edge, 0.4-0.6 x 0.3 mm, lips not obvious, most slightly gaping to expose hymenium, no pycnidia. The second, which is the more numerous on the UPS specimen, has only overmature ascomata with only lower wall still remaining. The ascomata are mostly elliptic to broad-elliptic, 0.4-0.6 x 0.3mm, rarely triangular, associasted with numerous, dark brown, pustulate, 0.2 mm diam. pycnidia. This second fungus apopears to match L. melaleucum sensu Eriksson. Eriksson records both L. melaleucum and L. oxyxocci on V. oxycoccos.

DESCRIPTION: [microscopic features from Eriksson collections only]
Ascomata developing in bleached areas of fallen leaves, sometimes with faint black or brown, possibly host-induced zone lines. Ascomata 0.4-0.8 x 0.3-0.4 mm, elliptic in outline with rounded ends, immature with pale to dark grey walls and no preformed line of dehiscence. Mature ascomata often with pale brown walls, with narrow black line marking outside edge of ascomata, or with dark brown to dark grey walls, opening by single longitudinal slit, not lined with obvious lip cells, ascomata often remaining open when dry with the brownish-yellow to dull orange-yellow hymenium remaining widely exposed. Pycnidia lacking.
Subcuticular. In vertical section immature ascomata upper wall up to 25 μm thick, tapering gradually to ouside of ascoma, of angular to irregularly-cylindrical, 2.5-5 μm, slightly thick-walled, brown to pale brown cells, appearance of the cells not varying over whole wall, except for poorly developed layer of short-cylindric, hyaline, thin-walled, periphysis-like cells lining inside of wall. Mature ascomata upper wall up to 30 μm thick, mostly of borown to pale brown, slightly thick-walled, angular, 2.5-5 μm diam. cells, but toward the base of the wall cells up to 10 μm diam., and here only the outermost cells darkened, the inner layers of cells form a broad connecting area between the upper and lower walls, and comprise similar, large, angular, hyaline cells. Exposed face of broken upper wall covered with loose, palisade-like layer about 10-15 μm wide of hyaline, thin-walled, cylindric, sometimes branched cells. Appears to be a poorly developed, about 10 μm wide excipulum-like layer between the hymenium and the upper wall, comprising 3-4 rows of hyaline, thin-walled, paraphysis-like elements, but closely septate, especially near the bases. Lower wall 25-30 μm thick, outermost 1-2 layers of cells 3-5 μm diam., angular, with outermost wall slightly thickened and brown, inside this is 3-4 cell wide layer of angular to globose, hyaline, slightly thick-walled, 5-8 μm diam. cells.
Paraphyses 1.5 μm diam., increasing more or less gradually to 4-5.5 μm diam. at the clavate to fusoid apex, extending up to 10 μm beyond asci. Asci 70-85 x 4.5-5.5 μm, subclavate, tapering to small rounded apex, wall undifferentiated at apex, 8-spored, spores confined to upper 40-45 μm of ascus with empty basal stalk, development sequential. Ascospores 20-26 x 1 μm, more or less straight when released, with small, about 2 μm diam., globose gelatinous cap, but otherwise without gelatinous sheath, 0 septate, more or less not tapering to base.

Notes from P.R. Johnston from the 1980's