The specific epithet “oblongifoliae” refers to the host plant Garciniaoblongifolia.

China, Hainan Province: Bawangling National Forest Park, on diseased leaves of Garciniaoblongifolia, 19 May 2021, Z.X. Zhang (holotype, HSAUP210052; ex-type SAUCC210052).

Leaf endogenic and associated with leaf spots. Asexual morph: Conidiomata pycnidial, mostly aggregated in clusters, black, erumpent. In MEA culture exuding colourless to opaque conidial masses within 10 days or longer. Pycnidial wall multilayered, textura angularis, brown to dark brown, up to 30 μm thick; inner walls hyaline. Conidiophores indistinct, often reduced to conidiogenous cells. Conidiogenous cells terminal, subcylindrical, ampulliform, hyaline, smooth, 9.0–14.0 × 2.5–4.5 μm. Conidia 8.0–13.0 × 6.0–8.0 μm, mean ± SD = 10.0 ± 1.3 × 7.2 ± 0.5 μm, hyaline, aseptate, thin and smooth walled, coarsely guttulate or with a single large central guttule, ovoid, ampulliform, ellipsoidal to subglobose, enclosed in a thin mucoid sheath, 1.0–2.0 μm thick and bearing a hyaline, apical mucoid appendage, 3.0–8.5 × 1.0–1.5 μm, flexible, unbranched, tapering towards an acutely rounded tip.

. Colonies on PDA occupying an entire 90 mm Petri dish in 14 days at 25 °C in darkness, with a growth rate of 6.0–6.5 mm/day, greenish-black in obverse and reverse. Colonies on MEA 82–86 mm in diameter after 14 days at 25 °C in darkness, with a growth rate of 5.7–6.2 mm/day, undulate at edge, white to grey white in obverse and reverse, with moderate aerial mycelia on the surface, with black, gregarious conidiomata.

China, Hainan Province: Bawangling National Forest Park, on diseased leaves of Garciniaoblongifolia, 19 May 2021, Z.X. Zhang, HSAUP210053, living culture SAUCC210053; on diseased leaves of Garciniaoblongifolia, 19 May 2021, Z.X. Zhang, paratype HSAUP210054, ex-paratype living culture SAUCC210054; on diseased leaves of Garciniaoblongifolia, 19 May 2021, Z.X. Zhang, paratype HSAUP210055, ex-paratype living culture SAUCC210055.

Phyllostictaoblongifoliae is introduced, based on the multi-locus phylogenetic analysis as the strain clustered into a well-supported clade (Fig. 1; 1.00/100), which is closely related to Phyllostictaugeniae (0.98/81), but distinguished, based on molecular data, ITS, LSU, tef1, ACT and GPDH loci by 57 nucleotide differences in the concatenated alignment. Morphologically, P.oblongifoliae (SAUCC210052) differs from P.ugeniae (CBS 445.82) in its shorter and wider conidia (8.0–13.0 × 6.0–8.0 vs. 9.6–16.8 × 4.8–6.0 μm) (Wikee et al. 2013a). Therefore, we establish this fungus as a novel species (Jeewon and Hyde 2016).