Nectria peristomialis (Berk. & Broome) Samuels 1976
Details
Nomenclature
Classification
Descriptions
Nectria peristomialis (Berk. & Broome) Samuels 1976
CONIDIAL STATE: Acremonium sp.
Mycelium white or not visible. sparse, and growing away from the perithecia. Perithecia solitary or in groups of 2-4, hyaline with orange contents, globose, 200-370 µm diam., with an apical, stellate crown of hairs, not collapsing when dry, not changing colour in 3% potassium hydroxide. Perithecial wall 30-40 µm thick. Surface view; cells prosenchymatous, walls 1-2 µm thick. Longitudinal section: outer region 10-20 µm wide, cells prosenchymatous, walls of cells 1-2 µm thick; inner region 15-20 µm wide, cells ellipsoidal, 3-7 µm long, walls 1-2 µm thick; cells becoming progressively more flattened toward the interior, merging with the cells of the prosenchymatous layer at the exterior. Perithecial hairs fasciculate, forming a stel.late apical disc or less frequently triangular and scattered, white, up to 200 µm long, 60-80 µm basally; composed of unbranched, septate, tightly bound, hyphae, c. 3 µm wide with walls c. 1 µm thick; arising from the prosenchymatous region of the outer perithecial wall. Perithecial papilla lacking, ostiolar opening formed by narrow hyphal elements arising from the inner region of the perithecial wall; ostiolar canal periph ysate. Asci clavate, (52-) 70-85 (-105) x (8-) 9-13 (-15) µm, 8-spored; apices rounded, simple; bases rounded; ascospores biseriate, forming throughout the length. Ascospores fusiform, (18-) 25-32 (-37) x (3-) 4-6 (-7) µm. 1-2 (-5) septate; coarse striations ridge-like and frequently forming a blunt apiculus at the ends of the ascospores; not constricted or cells separating at the median septum, hyaline.
CHARACTERISTICS IN CULTURE CMD: Ascospores germinating overnight; a single, long, unbranched germ tube arising from each end of each ascospore. Colonies 1 cm diam., opaque, white to pale pink; aerial mycelium lacking or as hyphal, rope-like strands; non-aromatic, medium non-pigmented. ME: Less than 1 cm diam., opaque, white to pink; aerial mycelium sparse to lacking or as hyphal, rope-like strands; margin undulate, non-aromatic, medium non-pigmented. OA: 1-2 cm diam., opaque, white to pale pink; aerial mycelium as hyphal, rope-like strands arising in concentric rings around the inoculum; non-aromatic, medium non-pigmented. WAS: 2 cm diam., transparent, grey, aerial mycelium sparse, margin undulate, non-aromatic, medium non-pigmented. Phialophores forming only on WAS, arising from the surface of the straw and from the aerial mycelium; monophialidic, unbranched, 0-2 septate, straight, smooth, (19-) 22-47 (-60) µm long, 2-3.5 µm basally, subtending hypha 2-3.5 µm wide. A solitary phialide constituting the terminal (7-) 23-33 µm of each phialophore, 1-1.5 µm wide at the unflared tip. Conidial production sparse. Phialoconidia ellipsoidal to nearly cylindrical. (4-) 5-7 (-8) x 2-2.5 µm, unicellular, hyaline, without a basal abscission scar. Arising in basipetal succession and held in a solitary, hyaline drop of liquid.
The apical fringe of hairs gives the perithecia `an apothecial aspect, thus explaining why the species has been treated as a discomycete.