SPECIMENS EXAMINED: COROMANDEL: Thames, Kauaeranga Valley, on indet. wood, Samuels (83-55) & Petersen, 1 May 1983 (PDD 45372); vic. Kawakawa Bay, Morehu Scenic Reserve, on buried, well rotted wood of Nothofagus fusca, Samuels (83-68) et al., 5 May 1983 (PDD 45337). GISBORNE: Urewera National Park. Lake Waikaremoana, track from Aniwaniwa to Lake Waikareiti, on wood in running water, Samuels (83-540,) et al., 29 May 1983 (PDD 45371); Lake Waikaremoana, track from Aniwamwa to Lake Ruapam, on Nothofagus sp., Samuels (82-70), 25 May 1982 (PDD 44304). BULLER: vic. Lyell Creek, c. 26 km S of Murchison, on indet. wood, Samuels (83-459) et al., 17 Apr. 1983 (PDD 45369); 22 km SE of Murchison P.O., on Murchison-Maruia Saddle road, on wood in running water, Samuels (85-81) et al., 7 May 1985 (PDD 47426). SOUTHLAND: Catlins State Forest Park, c. 20 km SW of Owaka, Table Hill Scenic Reserve, track to Matai Falls, on wood in running water, Samuels (85-76) et al., 18 Apr. 1985 (PDD 47418).

Stromata solitary or gregarious, unbranched, 1.5-2.0(-3.0) µm long, at first conidiogenous and white: perithecia intercalary and formed in 1 or 2 cylindrical clusters or, less frequently, forming over the entire length of the axis except on the acute apex, fertile portion 2 mm diam., perithecia completely immersed or nearly superficial; surface of the fertile portion somewhat tuberculate, with longitudinal splitting; brown tissue sometimes evident: perithecia) openings umbilicate to slightly papillate or not evident. Internal tissue white, solid. Stipe and axis sharply delimited from fertile portion, wiry, < 0.5 mm diam., black and glabrous or with fine tomentum of brown hyphae. Asci 170-200(-225) µm total length x (5.0-)5.5-7.0(-8.0) µm, sporiferous part (65-)72-95(-120) µm, cylindrical; apical ring J+, wedge-shaped, 2.0-2.5 µm wide x 2.0-4.5 µm high; 8-spored, ascospores uniseriate with overlapping ends. Ascospores (10.0-)11.5-13.5(-15.5) x 4.5-6.0(-6.5) µm, inequilateral with one side flat to concave and the other side rounded; elliptic in top view; transparent brown; slit slightly less than full length to full length, parallel to the long axis of the spore. Conidiophores in vivo forming in a white layer along the length of the filiform, < 0.5 mm diam., stromatal axis. Conidiophores forming a dense palisade; conidiogenous loci terminal with a 1 µm diam. refractive frill remaining after conidial dehiscence. Conidia (6.0-)7.2-10.7(-11.5) x 2-3 µm, narrowly elliptic to clavate, colourless, smooth: each with a 0.5 µm wide, flat, refractive basal abscission scar.
CHARACTERISTICS IN CULTURE: Colonies grown 3 weeks at 20°C diffuse daylight on OA 3-4 cm diam., flat or with conspicuously barraging hyphal ropes or young stromata around the depressed centre and with blackening in the centre of the colony; acute, 7 mm long stromata arising from the centre of the colony; stromata black below and white above, sterile.

DISTRIBUTION: NORTH ISLAND: Coromandel, Gisborne. SOUTH ISLAND: Buller, Westland, Southland,

HABITAT: Decorticated wood, most often in running water.

Xylaria hypoxylon is a complex species which will probably eventually be shown to include several taxa. It has been reported from almost every part of the world but seems most common in temperate regions. It is apparently not common in New Zealand, where it is most often found on blackened wood in running water.
Xylaria hypoxylon sometimes superficially resembles X. cf. filiformis in its wiry axis, but the former species is usually much more robust than the latter. They are separable on ascospore characters. Moreover, X. hypoxylon occurs on wood, whereas X. cf. filiformis occurs on herbaceous debris and leaves.
Xylaria hypoxylon has been cultured many times by various persons. Our New Zealand cultures greatly resemble those of Callan (1985) initiated from stromata collected in the western United States. Her cultures particularly resembled ours in production of sterile stromata. Conidia from naturally produced stromata were slightly larger than those reported herein (Callan 1985).