Nectria arenuloides Samuels 1976
CONIDIAL STATE: Acremonium sp.
Mycelium a fringe of white hyphae surrounding the base of each perithecium, not visible elsewhere, Perithecia solitary; at first white, becoming orange, glabrous and scaly, globose to tympaniform 250-310 tom diam., becoming collabent when dry, not changing colour in 3% potassium hydroxide. Perithecial wall 50-65 µm thick. Surface view: cells pseudoparenchymatous, 7-15 µm in greatest, dimension, walls 0.5-1.0 µm thick. Longtitudinal section: outer region 20-30 µm wide, cells elliptical, 5-15 µm long, 3-5 µm wide, walls 0.5-1.0 µm thick and pigmented; inner region 20-30 µm wide, cells elongated and compressed, outline of individual cells not apparent, walls 1-2 µm thick. Perithecial papilla lacking, ostiolar opening formed by narrow hyphal elements arising from the inner region of the Perithecial wall; ostiolar canal periphysate. Asci clavate, 60-80 (-100) x (9-) 10-18 An, 8-spored; apices rounded, immature asci appearing to have a pore that is not visible at maturity; bases rounded, ascospores biseriate, forming throughout the length. Ascospores fusiform, straight or curved, (13-) 19-22 (-24) x (3.5-) 4-1.5 (-5) µm, equally 2-celled, 4 striate, not constricted at the septum, hyaline.
CHARACTERISTICS IN CULTURE CMD: Ascospores germinating in low percentage overnight. Colonies 4-5 cm diam., transparent, white, aerial mycelium sparse, margin entire, aromatic, medium non-pigmented. Perithecia forming within 6-8 weeks in cultures derived from single ascospores. ME: 2.5-3 cm diam., barely transparent to translucent, white, aerial mycelium sparse, margin entire, aromatic, medium non-pigmented. OA: 3 cm diam., opaque; white, becoming pale pink; aerial mycelium dense, forming hyphal, rope-like strands; margin entire to slightly undulate, aromatic, medium non-pigmented. Perithecia forming within 6-8 weeks in cultures derived from solitary ascospores. WAS: 3 cm diam., transparent, aerial mycelium sparse, margin entire, non-aromatic, medium non-pigmented. Perithecia forming within 6 weeks in cultures derived from solitary ascospores. Phialophores arising on CMD, ME, OA, and WAS, forming from the surface of the agar and from the aerial mycelium; monophialidic, unbranched, 1-3 septate, straight, smooth, 70-110 jm long, 3-4 µm wide basally, subtending hypha 3-4 µm wide. A solitary phialide constituting the terminal 50-60 (-80) µm of each phialophore, 2-3 µm wide at the unflared or slightly flared tip. Conidial production sparse. Phialoconidia allantoid, elliptical to nearly cylindrical, (7-) 10-12 (-13) x (2.5-) 3-3.5 (-4) µm, unicellular, hyaline, with a slightly protuberant, flattened, basal abscission scar. Arising in basipetal succession, held in a solitary drop of hyaline liquid.