Diderma fragile Aramb., Bol. Soc. Argent. Bot.

Song, Wen-Long, Lin, Di, Li, Min, Du, Que & Chen, Shuang-Lin, 2022, Four new records of myxomycetes from China, Phytotaxa 567 (2), pp. 181-188 : 184-186

Diderma fragile Aramb., Bol. Soc. Argent. Bot. 15(2–3):175, 1973 ( Fig. 3 )

Sporangia grouped or dispersed, stalked, erect, 1.0– 1.5 mm in total height. Sporotheca subglobose, light yellow, 0.7–1.0 mm in diameter. Hypothallus membranous, reddish brown. Peridium double, the outer layer calcareous, eggshell-like, fragile, yellowish white, concolorous in the inner side but turning yellowish brown at the base of sporotheca, the inner layer membranous, colorless, inner layer is closely connected with the outer layer, dehiscence irregular, base constant persistence. Stalk slender cylindrical, erect, dark reddish brown, longitudinally grooved. Columella subglobose, 0.4– 0.5 mm in diameter, occupies almost 2/3 of the sporotheca, yellow, rough. Capillitium radiating from the columella, loose connection, threads 1.0–2.5 μm, scarcely branched, with irregular surface due to protuberances. Spores blackish in mass, reddish brown by transmitted light, globose, densely warted, 12.5–16.0 µm in diameter.

Specimen examined:— CHINA. Anhui Province: Yuexi County, Yaoluoping Nature Reserve , 31°98′41″N, 116°10′08″E, elevation 1204 m, on dead bark, 22 Oct 2021, collected by Que Du and Wenlong Song ( HFNNU 8542 ) .

Distribution:— Argentina ( Arambarri 1973), Spain ( Moreno et al. 1990), Peru ( Treviño-Zevallos & Rodriguez 2020), and China (this study).

Comments:— Diderma is a large genus of the family Didymiaceae in the order Physarales , with about 80 species reported and accepted ( Lado 2005 –2022), of which 26 species are known in China ( Chen et al. 2009, 2013). D. fragile is reported in China for the first time. There are few reports in the world of this species, only in Argentina, Spain and Peru. Our specimen was collected at 1204 m above sea level, but in Peru was collected at an altitude of 2851 m ( Treviño-Zevallos & Rodriguez 2020). Chinese specimens correspond to the original description ( Arambarri 1973) apart from a slightly longer stalk.

Figures

FIGURE 3. Morphological characters of Diderma fragile. a, b. Sporangia on bark. c, d. Spores (LM). e. Columella and stalk (SEM). f. Columella and capillitium are connected with each other (SEM). g. Granules in the cortex on the outer layer of peridium (SEM). h, i. Capillitium with surface protuberances (arrows, SEM). j, k. Spores showing the dense warts (SEM). Scale bars: a, b = 1 mm, c, d = 200 μm, e, f = 100 μm, g–k = 1 μm.