Polystichum xuansonense Li Bing Zhang, N. T. Lu & Liang Zhang 2023, sp. nov.
In: Three new species and one new record of the fern genus Polystichum (Dryopteridaceae) from Vietnam, pp. 85-94 in Phytotaxa 607(1) 89-90, 2023, S. 85-94
unknown
Zugriff:
Polystichum xuansonense Li Bing Zhang, N.T.Lu & Liang Zhang, sp. nov. (Figs. 3 & 4). Type:— VIETNAM. Phu Tho Province: Tan Son District, Xuan Son Commune, Xuan Son National Park, limestone mountain, 21° 7’58.11” N, 104°55’41.16” E, elev. ca. 345 m, 27 November 2013, Li Bing Zhang, Liang Zhang & Ngan T . Lu 6565 (holotype VNMN!; isotypes CDBI!, MO). Diagnosis:— This species is somewhat similar to Polystichum excellens Ching (1958: 234) in having oblong-lanceolate pinnae, but the former has middle pinnae with undulate to bluntly dentate acroscopic margins, proximal margins of pinnae parallel to or overlapping the rachis, and rounded pinna apex, whereas the latter has middle pinnae with low obtuse teeth or nearly repand acroscopic margins, proximal margins of pinnae forming an angle of 15–30° with the rachis, and acute pinna apex. Plants medium-sized, evergreen, (13–) 35–45 cm tall. Rhizomes erect, ca. 1.5 cm long, ca. 1.2 cm in diam.; roots brown blackish when dried, up to 20 cm long, ca. 0.5 mm in diam. Fronds 9–14 per rhizome, 10–43 cm; stipe brown, 4.5–10 cm long, ca. 1.0 mm in diam., basal stipe scales brown, membranous, lanceolate-ovate, 0.2–1.1 × 2.2–4.1 mm, margins entire, apex short acuminate; distal petiole scales lanceolate, subulate, 0.2–0.5 × 1.0– 2.12 mm, membranous, margins subentire to irregular dentate, apex long-acuminate or caudate. Laminae 1-pinnate, linear-lanceolate, 18–35 cm long, 2.3–4.5 cm wide, apex acuminate; rachises ca. 1 mm in diam., stramineous, adaxially sulcate; abaxially and adaxially with subulate scales, membranous, light brown, margins long outward, apex long-caudate. Pinnae 17–32 pairs, alternate, attached at 70° (–90°) angles to rachis, separate from each other, 0.6–1.2 cm distant (between two adjacent points), acroscopic auriculate; basalmost pinnae rhombic-ovate, 0.5–1.2 × 2.0–6.0 mm, shortly stalked, 2 basal pairs ca. 0.5 mm apart, apices acute or obtuse, bases obviously asymmetrical, acroscopic margins blunt dentate, basiscopic margins entire; middle pinnae ...
Titel: |
Polystichum xuansonense Li Bing Zhang, N. T. Lu & Liang Zhang 2023, sp. nov.
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Autor/in / Beteiligte Person: | Lu, Ngan Thi ; Zhang, Liang ; Thanh, Nguyen Trung ; Toan, Le Chi ; Zhang, Li-Bing |
Link: |
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Zeitschrift: | Three new species and one new record of the fern genus Polystichum (Dryopteridaceae) from Vietnam, pp. 85-94 in Phytotaxa 607(1) 89-90, 2023, S. 85-94 |
Veröffentlichung: | 2023 |
Medientyp: | unknown |
DOI: | 10.5281/zenodo.8212255 |
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