Heterosphaeria linariae

Heterosphaeria linariae (Rabenh.) Rehm, Rabenh. Krypt.-Fl., Edn 2 1.3(lief. 30): 203 (1888) [1896]

= Heterosphaeria ovispora Leuchtm., Mycotaxon 28(2): 272 (1987)

= Heteropatella lacera Fuckel, Jb. nassau. Ver. Naturk. 27-28: 54 (1874) [1873-74]

Saprobic on dead stems of Euphorbia sp. and Linaria vulgaris. Sexual morph: see Leuchtmann (1987) and Ekanayaka et al. (2019). Asexual morph: Conidiomata 150–420 µm diam., 300–400 µm high, pycnidial, globose to subglobose or irregular in outline, semi-immersed to superficial, separate to gregarious or confluent, unilocular, glabrous, thick-walled, ostiolate, rugose. Ostiole 70–210 µm long, 80–150 µm wide, cylindrical or funnelled, single, centrally or excentricity located. Conidiomatal wall 10–70 µm wide, composed of dark brown, thick-walled cells of textura angularis to textura globosa. Conidiophores up to 70 µm long, hyaline, branched, septate, formed from the innermost layer of wall cells. Conidiogenous cells 8–25 × 2–3 µm, hyaline, enteroblastic, phialidic, cylindrical, smooth, with a slightly wider apex, proliferating, sympodially 2–4 times. Conidia 44–68 × 2–4 µm ( = 53 × 3 µm; n = 50), hyaline, fusiform, mostly 4-septate, occasionally 3-septate, slightly constricted at septa, guttulate, smooth-walled, bearing appendages, basal cell 2.4–10 µm ( = 7 µm), obconic with a truncate base, median cells with a total length 9–25.6 µm ( = 15), mostly 3, occasionally 2 or 4, cylindrical to doliiform, apical cell narrow conical and attenuated into an unbranched, cellular appendage 25–44 × 1–2 µm ( = 36 × 1.5 µm; n = 30), basal appendage 5–25 × 1–2 µm ( = 12 × 1.5 µm; n = 30), filiform, unbranched, attenuated, excentric.

Material examined: Austria, Nassau, Dombachsgraben, on dead stem of Linaria vulgaris Hill (Plantaginaceae) (FH 01142398, Fuckel -Fungi Rhenani Edn. I, #2565, isotype); Italy, Province of Forlì-Cesena, Bagno di Romagna, Alfero, on dead aerial stems of Silene sp. (Caryophyllaceae), 6 April 2016, Nello Camporesi, IT2922 (MFLU 16-1154, reference specimen designated here), (KUN, HKAS 97463); ibid., Province of Arezzo, Pieve Santo Stefano, Montalone, on dead aerial stems of Euphorbia sp. (Euphorbiaceae), 2 May 2014, Erio Camporesi, IT1847 (MFLU 19-2866).

Notes: The sequences of our collection were obtained by direct sequencing. The LSU sequence of (MFLU 19-2866/IT1847) and (MFLU 16–1154/IT2922) is 99% or 100% similar to H. linariae (CBS 163.27, MFLU 15-2764, CBS 636.86, KP 2019a). There are four base pairs difference between the ITS (including 2 gaps) and rpb2 sequence of (MFLU 16–1154/IT2922) and H. linariae (CBS 163.27). The description of (MFLU 16–1154/IT IT2922) and (MFLU 19-2866/IT1847) is in accordance with the asexual morph of H. linariae. The dimensions of these two collections are in the range of the asexual morph of H. linariae [(43–64 × (2.5–)3–4 ( = 53.5 × 3.5 µm)] (Nag Raj 1993), and 42–78.5 × 2.6–4 ( = 55.6 × 3.2 µm).

Heterosphaeria linariae (asexual morph, FH 01142398, isotype) a, b Herbarium specimen. c, d Appearance of black conidiomata on the host surface. e–f, h Vertical sections of conidiomata. g Section of peridium. i–l Conidiophores, conidiogenous cells and developing conidia. m–p Conidia. Scale bars c–f = 200 µm, g–h = 50 µm, i = 20 µm, j–p = 10 µm.