Xylariales » Xylariales, genus incertae sedis » Botryohypoxylon

Botryohypoxylon amazonense

Botryohypoxylon amazonense Samuels & J.D. Rogers, Mycotaxon 25(2): 633 (1986)                                         Fig. 65

Index Fungorum number: 214383; Facesoffungi number: FoF 06221

Parasitic or lignicolous on dead trunks of tree. Sexual morph: Ascostromata rarely solitary, often cespitose in groups of 2–20, individually 600–700 µm diam. with locule 550 µm diam, ostiolate, thickened subiculum. Each ascoma arise on a cylindrical 1 mm long × 0.5 mm wide pedestal, globose with a tiny, acute papilla, only slightly wider than the pedestal, smooth, not collapsing when dry. Peridium 130 µm thick, with three discrete regions. Outer region 26–37 µm wide, composed of cells of textura angularis, with long axes perpendicular to the surface of the ascomatal wall, individual cells 7–9 µm in greatest dimension with pigmented walls 1-2 µm thick. Middle region 25–35 µm wide, composed of cells of textura epidermoidea. Inner region 10–20 µm wide, the eel is fusoid, non- pigmented. Ascomatal apex composed of intertwined hyphae with lumens 1–2 µm wide and 3 µm thick and pigmented with finger-like periphyses. Pseudoparaphyses 2 µm wide, forming a network between the asci, copious, branching, anastomosing, free ends not seen. Asci 51–85 µm × 6–9 µm (x̅ =  65.8 × 8.0, n = 20), 8-spored, unitunicate with thin ectoascus and endoascus rather thick throughout the entire length of the ascus, clavate, ascal cytoplasm abruptly narrowed below the ascospores at the point of dehiscence, dehiscing at the midpoint, forming a hymenium over the entire interior of the ascomatal wall. Ascospores 6.7–7.9 µm × 4.3–5.0 µm (x̅ = 7.1 × 4.5, n = 20), uni to biseriate, ellipsoidal, unicellular, hyaline when immature, dark brown, nearly opaque when mature, smooth-walled. Asexual morph: Undetermined.

Material examined VENEZUELA, on trunks of dead tree (Leguminosae), along Rio Mawarinuma, just outside Canon Grande vicinity of Neblina base camp, ca. 140 m, 00o50’N, 66o10’W; low primary forest on white sand, 30 April 1984, Gary J. Samuels (1703) & W. Thomas, (NY02980804, holotype).

Economic significance – The genus Botryohypoxylon is parasitic or possibly lignicolous on trees in Amazonian Venezuela. No other economic significance havehas been reported (Samuels & Roger 1986).