Melanographium citri (Gonz. Frag. & Cif.) M. B. Ellis

Melanographium citri (Gonz. Frag. & Cif.) M. B. Ellis View in CoL , Mycological Papers 93: 21 (1963)

Fig. 2 View Figure 2

Description.

Saprobic on a dry palm branch. Sexual morph: Ascomata 440–680 µm wide, 470–540 µm high, immersed, solitary or gregarious, appearing as small black spot, in cross-section globose to subglobose with a flattened base. Ostioles centric, slightly papillate, black, slightly higher than the surface of the host. Peridium 12–27.4 µm thick, comprised of two layers; outer layer composed of thick-walled, dark-brown, cells of textura angularis; inner layer composed of thin-walled, hyaline, cells of textura angularis. Paraphyses 2–5 µm (x ̄ = 3 µm, n = 30) wide, longer than the asci, numerous, filamentous, guttulate. Asci 185–260 × 15–35 µm (x ̄ = 216 × 23 µm, n = 30) 8 - spored, unitunicate, clavate-cylindrical, short-pedicellate, apically rounded, with non-amyloid apical apparatus. Ascospores 20–27.5 × 8.5–11.5 µm (x ̄ = 25 × 10 µm, n = 30), overlapping unicellular, fusiform with rounded ends, dark brown, covered with a thick mucilaginous sheath measuring 4–14.5 µm (x ̄ = 8.0 µm, n = 30), with a straight germ slit on the centre, ca. 1 / 4 of the length of the spore. Asexual morph: not found.

Culture characteristics.

Ascospores germinated on PDA within 24 hours. Colonies reaching 55 mm diam., after 4 weeks at 24–27 ° C on PDA. Colony surface white towards edges, dirty brown at centre, with densely mycelium, cottony, circular, velvety, smooth-edged, centre raised; reverse pale brown.

Material examined.

China • Yunnan Province, Ailaoshan National Nature Reserve ( 24°5'7.01"N, 101°31'30.44"E), altitude: 1169 m, on a dead palm branch, 15 September 2024, Changtao Lu, 2024 ALS 45 ( GMB 4902 ; GMBC 4902 ) GoogleMaps ; China • Yunnan Province, Ailaoshan National Nature Reserve ( 24°5'28.15"N, 101°31'45.23"E), altitude: 1172 m, on a dry palm branch, 16 September 2024, Changtao Lu, 2024 ALS 267 ( GMB 4951 , GMBC 4951 ) GoogleMaps .

Notes.

Our collections ( GMB 4902 and GMB 4951 ) clustered with M. citri with strong support (100 BS / 1.00 PP) (Fig. 1 View Figure 1 ). Melanographium citri has previously been known only from the asexual state ( Ellis 1963; Zhang et al. 2024), whereas our collections represent solely the sexual state, which precludes direct morphological comparison. Molecular comparison between our collections ( GMB 4902 , GMB 4951 ) and the reference specimen of M. citri ( HKAS 115665 , Zhang et al. (2024)) revealed minimal differences, 1.1 % (6 / 536 bp) in ITS, 0.4 % (4 / 853 bp) in LSU, 0.3 % (3 / 1009 bp) in rpb 2 and 0.2 % (2 / 934 bp) in tef- 1 α. Given the high sequence similarity (> 99 % in both rpb 2 and tef 1 - α), along with prior documentation of this species from south-western China ( Zhang et al. 2024), we identify our collections as Melanographium citri . Ecologically, M. citri has so far been reported exclusively from palm substrates ( Arecaceae ), including decaying petioles of Trachycarpus fortunei and the wood or bark of Cocos , Elaeis , Phoenix , Sabal and Trachycarpus spp. ( Ellis 1963; Zhang et al. 2024), whereas our specimens were isolated from decaying bamboo culms ( Poaceae ), representing a novel substrate record. The ecological difference in host substrate suggests expansion of the known ecological range of this species.

With this report, we present the first documentation of the sexual state in Melanographium , characterised by globose to subglobose ascomata, eight-spored, clavate to cylindrical, non-amyloid asci and fusiform, dark brown ascospores with rounded ends, a short germ slit and a mucilaginous sheath. Phylogenetically, Melanographium species forms a distinct clade at the basal of Pallidoperidiaceae . It differs from other genera in Pallidoperidiaceae ( Sugita et al. 2024; Habib et al. 2025) by its fusiform ascospores with a short germ slit at the centre and relatively wider asci with non-amyloid apical apparatus. Amphigermslita species possess amyloid, wedge-shaped apical apparatuses and ellipsoid to fusoid ascospores with short germ slits at both ends ( Sugita et al. 2024; Habib et al. 2025). Crassipseudostroma is distinguished by fusiform to ellipsoid ascospores with mucilaginous pads and a full-length germ slit. Minuticlypeus and Nigropunctata have cylindrical asci with amyloid apical apparatuses and ellipsoid to oblong ascospores with germ slits extending the full length of the spore ( Sugita et al. 2024).