Ascomata subcuticular. In vertical section upper wall of unopened ascomata up to 50 µm thick, thinner toward the edges of the ascomata. Wall comprising mostly brown to pale brown, angular cells, darker toward the outside of the wall. In the inner half of the wall, along the future line of opening, is an ill-defined area of paler, thinner walled cells. Inside edge of the wall is lined with an irregular, 1-cell-wide layer of hyaline, cylindric to globose cells. In opened ascomata the upper wall is up to 80 µm thick near the ascomatal opening, becoming gradually thinner toward the base. Upper wall comprising brown to dark brown, thick-walled, globose to angular, 4-10 µm diam. cells. Exposed face of the broken upper wall is lined with a layer of hyaline, thin-walled, cylindric, 15-25 x 3-4 µm cells. Lower wall 8-15 µm thick, of 2-3 layers of brown, thick-walled, cylindric to angular, 3-6 µm diam. cells.

Paraphyses 1-2 µm diam., circinate at apex, extending 5-10 µm beyond asci. Asci 110-155 x 8.5-10.5 µm, clavate-stipitate, tapering to rounded apex, wall undifferentiated at apex, 8-spored, spores confined to upper half of ascus. Ascospores 24-38 x 2.0-2.5 µm (average 32.8 x 2.1 µm), cylindric-bifusiform, apex rounded, tapering to base, slight constriction near centre of the spore, hyaline, 0-septate, surrounded by narrow gelatinous sheath. Conidiomata subcuticular. In vertical section upper wall more or less lacking, or up to 5-8 µm thick, comprising dense, dark brown to black material with no obvious cellular structure. Lower wall 10-15 µm thick, of 2-3 layers of dark brown, thick-walled, cylindric cells. Lower wall lined with 2-3 layers of hyaline, thin-walled, angular cells on which the conidiogenous layer develops. Columns of sterile cells may extent between the upper and lower wall near the centre of the conidiomata. Conidiogenous cells 7.5-12.0 x 1.5-2.5 µm, more or less cylindric, proliferation percurrent, wall of conidiogenous cell slightly thickened and often flaring at the apical conidiogenous locus. Conidia 3-4 x 1-1.5 µm, cylindric, ends rounded, hyaline, 0-septate.

CHARACTERISTICS IN CULTURE: A few ascospores from PDD 43266 and PDD 46711 germinated on agar plates after48 hours. Colonies on OA 30-40 mm diam. after 8 weeks, aerial mycelium grey, dense, cottony to felted, agar surface dark brown near centre of colony, reddish toward edge with red pigment diffusing into agar around colony. Remaining sterile.

ETYMOLOGY: obtectum = covered over; refers to sparse layer of mycelium covering the upper wall of the ascomata.

NOTES: H. obtectum is easily distinguished from other New Zealand species by the wispy, yellow or white, aerial hyphae surrounding the ascomata, and by the size and distinctive shape of its ascospores.