Avettaea salvadorae (Petr.) Abbas & B. Sutton, Trans. Br. Mycol. Soc.

Sánchez, Romina M. & Bianchinotti, M. Virginia, 2023, New records of mitosporic ascomycetes on Nothofagaceae from Patagonia, Argentina, Boletin de la Sociedad Argentina de Botanica 58 (4), pp. 491-503 : 493

1. Avettaea salvadorae (Petr.) Abbas & B. Sutton, Trans. Br. Mycol. Soc. 90: 491. 1988. Fig. 1 A-F.

Conidiomata pycnidial, spheroidal, subperidermic, dark brown to black, ca. 158 µm diam., 132-138 µm high (M = 134.9); peridium of textura epidermoidea, ca. 20 µm thick. Conidiophores absent or represented by a cylindrical to quadrangular subhyaline cell, ca. 5 µm high. Conidiogenous cells ampulliform, enteroblastic, annelidic, with a small collarette, discrete or integrated, percurrent, smooth, hyaline, 9-15 × 2-5 µm (M = 10.9 × 2.9). Conidia slightly obovoid, enclosed by mucilaginous sheath (0.5-2 µm wide), aseptate, smooth, hyaline, 9-16 × 7-12 µm (M = 12.6 × 9.8; n = 20).

Distribution and habitat. Growing on twigs of Geoffroea decorticans (Gillies ex Hook. & Arn.) Burkart ( Bianchinotti, 1993) and on bark of Nothofagus pumilio in Argentina . On Salvadora oleoides Decne. and S. persica L. in India and Pakistan ( Abbas & Sutton, 1988).

Comments. The specimen described here is assigned to A. salvadorae because of the presence of enteroblastic conidiogenous cells and the size of conidia, which are the biggest in the genus (8-21.5 × 9-17.5 µm). The species is easily distinguishable from the other two in the genus, A. alcornii Sivan. & B. Sutton and A. philippinensis Petr. & Syd. , because the first has holoblastic conidiogenous cells (4.5-7 µm high) and smaller (9-11 µm diam.), spherical, verrucose conidia, with a very thin, persistent mucilaginous sheath (less than 1 µm). The second, which is the type species, differs because conidia, of less size, are ellipsoidal to ovoid (6-10 × 4.5-5.5 µm) and are devoid of conidial sheath when mature.

Material examined. ARGENTINA. Prov. Chubut: Parque Nacional Los Alerces, ca. 12 km on the way to Lago Baggilt (43° 15′ 59.76″ S, 71° 39′ 2.52″ W), 1079 m alt., on bark of N. pumilio , 15- V-2007, Bianchinotti & Sánchez 545 ( BBB) .

Figures

Fig. 1. Avettaea salvadorae. A: Pycnidial conidioma on substrate. B: Vertical section of a pycnidial conidioma. C: Conidiogenous cell. D: Conidiogenous cell with two annelidic percurrences. E: Conidium before liberation from conidiogenous cell. F: Conidia. Bactrodesmium atrum. G: Sporodochial conidioma on substrate. H: Conidium detached from conidiogenous cell and view of the conidiophore. I: Conidium 6 septate, septa visible by constrictions. J: Conidium with ornamented wall. Abbreviations: cg: conidiogenous cell; sh: sheath; sp: septa. Scale bars= A, G: 100 µm; B: 40 µm; C-D: 2 µm; E: 5 µm; F: 10 µm; H-J: 20 µm.