Dryopteris subdiffracta H. J. Wei & Z. Y. Zuo 2024, nothosp. nov.

Dryopteris × subdiffracta H. J. Wei & Z. Y. Zuo nothosp. nov. Figs 3, 4, 5 C, D ≡ D. diffracta (Baker) C. Chr. × D. polita Rosenst. Type. China • Guangxi: Jinxiu county, Mt. Shengtangshan, in broad-leaved forest, 23°58'11"N, 116°6'54"E, elev. 1156 m, 9 May 2018, She-Lang Jin, Jing Liu, Qi-MingTang & Xu Yan JSL 6337 (holotype: CSH 0200999!; isotypes: CSH!, IBK!, KUN!). Diagnosis. Dryopteris × subdiffracta is similar to D. × subreflexipinna in having slightly flexuous rachis and deflexed pinna stalks, but the former has a tripinnate to tripinnate-pinnatisect frond, narrowly ovate or oblong pinnulets with obtuse apex and nearly symmetric base, while the latter has 4 - pinnate frond, ovate pinnulets with round or obtuse-rounded apex and asymmetric base. Description. Rhizome erect, densely covered with brown scales at apex. Frond (42 –) 50–84 cm; stipe stramineous, (23 –) 26–56 cm, (1 –) 1.5–3 mm in diam. at middle part, sparsely covered with scale at base, upwards glabrous, grooved adaxially; scales lanceolate, ca. 16 × 2.4 mm, brown, entire; lamina 3 - pinnate to nearly 4 - pinnate, deltoid to ovate-deltoid, (22 –) 27–43 × (15 –) 25–34 cm, base round or broadly cuneate, apex acuminate, rachis somewhat flexuous; pinnae 8–12 pairs, triangular-lanceolate, slightly falcate, alternate, lowest pair sometimes opposite to nearly opposite, stalked, stalks of lower pinnae slightly deflexed, bases forming an angle of ca. 70–85 ° with rachis, upswept distally, 2–6.5 cm apart from each other, stalks of middle pinnae spreading; lowest pinna largest, deltoid, (9 –) 12–21 × (6 –) 7–13 cm, base broadly cuneate or truncate, apex acuminate, stalk (1.5 –) 2–4 cm; pinnules 8–12 pairs, often anadromous, 1 - or 2 - pinnate, alternate, spreading, triangular-lanceolate, apex shortly acuminate, proximal pairs shortly stalked, bases broadly cuneate or shallowly cordate, nearly symmetrical, distal pairs of pinnules nearly sessile, bases asymmetrical, acroscopically broadly cuneate, basiscopically cuneate, basal acroscopic pinnule of pinna as large as or slightly smaller than adjacent ones, basal basiscopic pinnule on lowest pinna largest, (3.6 –) 5.5–7.5 (– 9) × (1.7 –) 2–3.7 cm, shortly acuminate, stalklet (1.5 –) 2–4 mm; pinnulets 6–10 pairs, often anadromous, proximal 2–5 pairs free, alternate, spreading to ascending, ovate to ovate-oblong, basal acroscopic one as large as or slightly larger than basiscopic one, bases of proximal pair rounded-cuneate, nearly symmetrical, bases of others rounded-cuneate to cuneate acroscopically, cuneate to narrowly cuneate basiscopically, apex blunt, acute to subacute, with 1 or 2 short obtuse teeth, larger pinnules (9.5 –) 11–18 × (5.5 –) 6.5–11 mm, stalklet 0.5–2 mm, pinnatifid or pinnatisect at base, with 1 or 2 free lobes proximally; lobes 1–3 pairs, ovate, narrowly ovate or oblong, ascending, margin undulant to entire, base narrowly cuneate, apex obtuse, entire or with 1 or 2 short obtuse teeth, larger lobes 3–6 × 2–3 mm; upper pinnae gradually reduced, spreading to oblique; lamina herbaceous, green on adaxial surface and light green on abaxial surface when dry, both surfaces glabrous, rachis and rachillae of every order stramineous, nearly glabrous expect for several hair-like scales on midribs and rachillae on abaxial surface, grooved adaxially; veins indistinct on adaxial surface, visible on abaxial surface, pinnate on pinnulets, veinlets forked or simple on lobes, not reaching margin; sori medial or slightly nearer to margin than to costa, terminal on veinlets, 1–3 pairs on each ultimate lobes; indusium brown, papery, entire, fugacious. Geographical distribution and ecology. Dryopteris × subdiffracta was found in Jinxiu, Shangling and Wumin County, Guangxi Zhuang Autonomous Region, South China (Fig. 6), always growing together with D. diffracta and D. polita in broad-leaved forests at the elevation of 800–1200 m. We noticed that two specimens of D. × subreflexipinna (TAI 270081, TAI 270101) collected from Taiwan are consistent with the characteristics of the new hybrid. There is a strong possibility that these two specimens were collected in the area where D. diffracta coexisted with D. polita. Dryopteris × subdiffracta might be distributed to Taiwan. Etymology. The specific name is derived from the Latin prefix sub- (close to), and diffracta, epitheton of a species, referring the new species is closely related to Dryopteris diffracta. Chinese name. 曲轴鳞毛蕨 (qū zhóu lín máo jué). Paratypes. China • Guangxi: Same place as the holotype, 1100–1200 m, 9 May 2018, She-Lang Jin, Jing Liu, Qi-MingTang & Xu Yan JSL 6341 (CSH!), Jing Liu, She-Lang Jin, Qi-MingTang & Xu Yan DYS 426, DYS 427, DYS 428 (IBK!) • ibid., 15 Aug. 2023, Zheng-Yu Zuo Zuo 5589 (KUN!) • ibid., 2 Mar. 2024, Ming-jin Wei & Yu-jin Wei JSL 9482 (CSH!). Additional specimens examined. China • Guangxi: Wumin County, Mt. Damingshan, Gannanhe (Ganlanhe), elev. 800–1000 m, 14 Sep. 1991, Hou-Gao Zhou & Hua Li 2769 (IBK!) • Shangling County, Mt. Damingshan, Ganlanhe, elev. 900 m, 16 Jul. 2011, Lei Wu & She-Lang Jin D 2760 (IBK!).