Diplocarpa constans H.L. Su & Q. Zhao, 2022

Su, Hongli, Chethana, K. W. Thilini, Li, Lu, Li, Wenchun & Zhao, Qi, 2022, Diplocarpa constans sp. nov., a new species of Cordieritidaceae from Yunnan, China, Phytotaxa 561 (1), pp. 75-84 : 78-81

Diplocarpa constans H.L. Su & Q. Zhao , sp. nov. Fig. 2

Diagnosis: Differs from other Diplocarpa species by the negative ionomidotic reaction of the excipulum.

Index Fungorum number: 559713; Facesoffungi number: FoF 11440; MycoBank number: MB 845303

Etymology: The specific epithet refers to its negative ionomidotic reaction, which is different from other species of Diplocarpa .

Holotype: HKAS 124025

Growing on decayed stems. Sexual morph: Apothecia 2–5 mm diam, up to 2 mm high when fresh, superficial, scattered or grouped, discoid to shallow cupulate, slightly leathery, shortly stipitate without a common base. Receptacle discoid to cupulate, greyish-green when fresh, light green when dry, excipulum with a negative ionomidotic reaction. Margin slightly involute to flat, light green. Hairs 25–50 × 3–5 µm (x̄ = 35 × 4 µm, n = 17), clavate with rounded apex, straight to slightly curved, smooth, thick-walled, septate, hyaline at the top, green at the base, covering the whole receptacle and margin, and not macroscopically. Ectal excipulum comprised of textura angularis -globulosa cells, 25–45 µm (x̄ = 35 µm, n = 13) thick in receptacle, and 65–105 µm (x̄ = 80 µm, n = 12) thick on the stipe, dark brownish, cortical cells with hairs, cells hyaline to light brownish in the inner layers of receptacle, light brown to brownish in the outer layers of receptacle and stipe, 8–40 × 4–24 µm (x̄ = 16 × 11 µm, n = 48), slightly thick-walled cells. Medullary excipulum comprised of textura intricata cells, 50–195 µm (x̄ = 95 µm, n = 21), brownish, 3–15 × 2–7 µm (x̄ = 4 × 7 µm, n = 51), thick-walled. Hymenium 70–105 µm (x̄ = 90 µm, n = 10), slightly concave to flat, smooth, dark olive-green when fresh, yellowish green when dry. Paraphyses longer than asci, filiform, unbranched, smooth, thin-walled, septate, with conspicuous tips of 15–20(–25) × 4–6 µm (x̄ = 20 × 5 µm, n = 15), fusoid, 1–3-septate, terminal and secondary cells yellowish green to olive-green when mature, lower cells hyaline, 1.0–2.3 µm (x̄ = 1.5 µm, n = 42). Asci 60–75 × 6–8(–9) µm (x̄ = 65 × 7 µm, n = 21), cylindrical-clavate, inoperculate, 8-spored, uniseriate, hyaline, rounded apex, wall apically thickened and laterally thin, with a ocular chamber, inamyloid, base slightly tapered, with croziers. Ascospores ellipsoid with rounded ends, slightly smooth, thin-walled, aseptate, hyaline, (154/4/2) 7.0–10.0(–11.0) × (3.5–)4.0–5.5 µm, (x̄ = 8.4 × 4.4µm, Q = 1.4–2.5, Q = 1.94±0.22), with 1–2 polar oil guttules. Asexual morph: Unknown.

Material examined: China, Yunnan, Ailao Mountains , alt. 2428 m, on bark of a dead branch, 2 September 2021, H.L. Su, SHL224 ( HKAS 124025 , holotype); ibid., alt. 2434 m, on a dead bark, 1 September 2021, H.L. Su, SHL247 ( HKAS 124026 , paratype) .

Notes: The new species is characterized by discoid to cupulate apothecia with green receptacles, green hairs, excipulum with a negative ionomidotic reaction, aseptate ascospores. In the phylogenetic tree, Diplocarpa constans is clustered sister to D. bloxamii , and they are significantly different in the ionomidotic reaction; the former has a negative ionomidotic reaction, while the latter has a deep blood-red ionomidotic reaction. Besides, D. constans has brown receptacles, brown hairs and aseptate ascospores, whereas D. bloxamii has green receptacles, green hairs and septate ascospores ( Table 2 ).

Figures

FIGURE 2. Diplocarpa constans (HKAS 124025, holotype) a Habitat. b–f Dry and fresh apothecia. g Vertical section of the apothecium. h Ectal and medullary excipulum. i Ectal excipulum at the stipe. j, k Hairs. l–n Asci. o Paraphyses. p Apex of a paraphysis. q Apex of an ascus. r Base of an ascus. s–v Ascospores. Scale bars: b = 1cm, c–f = 2mm, g = 200 µm, h–i = 50 µm, j–o = 20 µm, p–r = 10 µm, s–v = 5 µm.