Diderma liaoningensis H. N. Zhao, B. Zhang & Y. Li, 2022

Zhao, Hui-Nan, Rao, Gu, Yang, Xin-Ya, Li, Xiao, Yu, Hai-Long, Zhang, Bo & Li, Yu, 2022, Two new species of Diderma (Physarales, Didymiaceae) from northern China, Phytotaxa 572 (1), pp. 61-73 : 66

Diderma liaoningensis H. N. Zhao, B. Zhang & Y. Li , sp. nov. FIGURE 2 .

MycoBank No.: 842350

GenBank No.: OM258681 , OM258682 , OM258683 (SSU rRNA gene).

Holotype: CHINA. Liaoning Province: Fuxin city, Haitang Mountain Scenic Spot, 41°48.30′N, 121°47.15′E, on decaying branches, 2 September 2012, collected by Zhang Bo (Holotype, HMJAU 60224 !).

Etymology. The epithet “liaoningensis” refers to Liaoning, the location of the holotype.

Description. Sporocarps grouped in small dense groups, Spherical to hemispherical 0.63–0.84 mm in diameter, crowded, sessile, yellow-white; Hypothallus profusely developed, white to cream-white. Peridium typically doublelayered, wrinkled, the ridges marking the line of dehiscence, dehiscing along the ridges into irregular and polyhedral fragments, the outer layer calcareous, composed of closely adherent lime granules, closely attached to the inner layer, light yellowish-brown; Columella white to pale yellow, clavate, rough; Capillitium abundant, light brown, one free and the other attached to the columella, branched and anastomosed, the ends shrink and form a thin line, 6.5 µm at the base, sometimes with membranous extensions at branching points, up to 16.5 µm in width, with brown swelling, up to 3–9 um in width; Spores black in mass, brown in transmitted light, spherical, with warts and a pale line, (12)12.9– 17.2(18) µm in diameter. DFa=0.75± 0.09 mm ( TABLE 2 ), avR=14.24–15.28 µm ( TABLE 3 ).

Habitat and distribution. On decaying branches in autumn.

Additional specimens examined. China. Liaoning Province: Fuxin city, Haitang Mountain Scenic Spot, 41°47.37′N, 121°43.20′E, on decaying branches, 1 September 2012, collected by Bo Zhang ( HMJAU 60275 , HMJAU 60276 , HMJAU 60277 ) ; Liaoning Province: Fuxin city, Haitang Mountain Scenic Spot, 41°47.48′N, 121°43.20′E, on decaying branches, 1 September 2012, collected by Bo Zhang ( HMJAU 60279 , HMJAU 60280 ), HMJAU 60281 , HMJAU 60285 , HMJAU 60286 , HMJAU 60225 , HMJAU 60227 ); Liaoning Province: Fuxin city, Haitang Mountain Scenic Spot, 41°48.30′N, 121°47.15′E, on decaying branches, 2 September 2012, collected by Bo Zhang ( HMJAU 60226 ) .

Notes. Diderma liaoningensis is characterized by grouped sporocarps, the sporocyst with dehiscence lines, capillitium with large brown swelling, and the spore encircled by a pale line. Morphologically and phylogenetically, D. liaoningensis is significantly related to D. crustaceum (Chou 1978; Buyck 1982), D. subdictyospermum ( Thind and Lakhanpal 1968; Liu and Chen et al. 1999; Lado et al. 2003), and D. cingulatum (Chou 1978; Nannenga-Bremekamp 1968) based on its white globes to hemispheric sporocarps and its white to yellowish-white columella. However, D. liaoningensis differs from D. crustaceum due to its sporocyst with dehiscence lines, closely adherent inner-outer layers peridium, and spore size and ornamentation. The spores of D. liaoningensis [(12)12.9–17.2(18) µm in diameter] are larger than those of D. crustaceum (10–12 µm in diameter). The spore of the D. liaoningensis has been encircled by a pale line. D. liaoningensis is easily confused with D. cingulatum due to their highly similar morphology. However, D. liaoningensis is differed from D. cingulatum by its spherical spore, and its capillitia with larger membranous extensions. D. liaoningensi can be distinguished from D. subdictyospermum by its larger spore and spore decoration. The spores of D. liaoningensis are (12)12.9–17.2(18) µm in diameter and have ridges about 2 µm high, whereas the spore of D. subdictyospermum is smaller (10–12 µm in diameter) than D. liaoningensis .

Figures

FIGURE 2. Habitat and microstructure of D. liaoningensis (HMJAU 60224 Holotype!) A Sporocysts. B–C Outer and inner layer of peridium. D Light yellow columella. E–F Capillitia and some spores. G–H Spores with warts. I–J Spores encircled by a pale line. Scale bars: 2mm (A); 500 μm (B); 200 μm (C, D); 20 μm (E, F); 10 μm (G, H, I, J)