Hyalopsora minispora Y.M. Liang & S.T. Liu, sp. nov. (Fig. 2)

MycoBank no: MB 830428.

Holotype:— China, Jiangxi Prov., 24˚59′54″N, 115˚30′59”E, 523 m asl, on Blechnopsis orientalis (Blechnaceae), 13 May 2018, Y.M. Liang and Y. Liu, BJFC-R03350.

Etymology:—Minispora, referring to its small urediniospores.

Distribution:— China (Jiangxi Prov.)

Uredinia mainly on the adaxial surface of fronds, sometimes bulging on both sides, hence appearing to be amphigenous, minute, 0.1–0.4 mm, subepidermal, round or elliptical, scattered, sometimes confluent, covered by a compact peridium at first, erumpent when mature, pale yellow to yellow; fresh urediniospores and amphispores with yellow contents fade over time. Urediniospores elongate, ovoid, sub-pyriform, or obovate-elliptic, 16.5–23.0 × 11.0–19.0 μm (x = 21.0 × 15.0 μm, n = 50); walls colorless, 1.0–2.0 μm thick, finely echinulate, with 4 – 6 scattered pores. Amphispores oblong, ellipsoid, obovate, or polygonal, sometimes angular, 18.5–29.0 × 15.5–23.0 μm (x = 24.0 × 19.5 μm, n = 50), walls 2.0–4.0 μm thick, hyaline, nearly smooth, with 4–6 scattered pores.

Additional specimen examined:— China, Jiangxi Prov., 25˚37′26″ N, 114˚18′25” E, 1138 m asl, on Metathelypteris laxa (Thelypteridaceae), 22 July 2018, Y. M. Liang, C. M. Tian, and Y. Liu, BJFC-R 03351.

Notes:— Hyalopsora minispora is similar to H. cryptogrammes and H. hakodatens in spore size. However, H. minispora has both urediniospores and amphispores while H. cryptogrammes has only urediniospores (Sydow & Sydow 1914). Urediniospores of H. minispora have 4–6 scattered germ pores, but H. hakodatensis possesses only 2–4 germ pores at the equatorial region (Ji et al. 2018). H. minispora shares the host Blechnopsis with H. aculeata and H. polypodii (Ono 2017). However, H. minispora has urediniospores and amphispores in the same uredinium, whereas H. aculeata has only urediniospores (Hiratsuka et al. 1992). H. minispora can be distinguished from H. polypodii by its smaller urediniospores (16.5–23.0 × 11.0–19.0 μm) with 4–6 scattered germ pores, those of H. polypodii are larger (18.0–37.5 × 8.0–22.5 μm) with 2–4 scattered germ pores (Azbukina 2015).