Xiphopterella parva Parris, 2015

Parris, Barbara, Chen, Cheng Wei, Hsu, Tian Chuan, Lu, Thi Ngan, Nguyen, Quoc Dat & Luu, Hong Truong, 2015, New species and records of grammitid ferns (Polypodiaceae) for Vietnam, Phytotaxa 226 (1), pp. 39-50 : 43

Xiphopterella parva Parris sp. nov. ( Figure 3 )

Type: — VIETNAM. Lam Dong Province: Lac Duong District, Da Chays Commune, Bidoup-Nui Ba National Park, Giang Ly Forest Station , elev. 1700 m, 20 June 2011, Wade 1626 (holotype SGN!; isotypes AK!, TAIF!) .

Xiphopterella parva differs from other members of the genus in the following combination of characters: lacking setae, having hydathodes on the vein endings on the adaxial surface of the lamina together with the rachis slightly prominent to prominent and slightly darker to darker on the abaxial surface, and level to slightly sunken and concolorous to slightly darker on the adaxial surface.

Rhizomes radial, stipes in whorls, not articulated to rhizome; rhizome scales 1.1–1.7 × 0.2–0.8 mm, pale red-brown, glabrous, not clathrate; stipes ± winged to base; laminae 21–32 × 3–5 mm, narrowly oblanceolate in outline, acute at apex, long-attenuate at base, deeply pinnately divided to wing 0.2–0.5 mm wide along rachis; pinnae 8–14 pairs, 2–3 × 1–2 mm, narrowly triangular; rachis slightly prominent to prominent and slightly darker to darker on abaxial surface, level to slightly sunken and concolorous to slightly darker on adaxial surface; veins simple in sterile pinnae, 1-forked in fertile pinnae, acroscopic branch much shorter than basiscopic branch, not extending beyond sorus, vein endings with pale hydathodes on adaxial surface; sori ± circular to broadly elliptic, in apical 1/4 to 2/5 of lamina, one row each side of rachis, 3–10 in each row, one per pinna; sporangia glabrous; whitish to pale red-brown 1–2 forked hairs with catenate base, setae as branches and glandular apex occasional to sparse on abaxial surface of rachis.

Distribution and habitat:—In mixed conifer-broadleaf forest. Vietnam, endemic.

Etymology: —Latin, parva = small, referring to its small size compared with the larger members of the genus.

Taxonomic note: — Xiphopterella devolii S.J. Moore, Parris & W.L. Chiou (2013: 54) occurring in Taiwan differs from X. parva by having larger laminae and longer lobes, with the rachis sometimes slightly prominent and concolorous to slightly darker on the abaxial surface and sunken and darker on the adaxial surface, sterile pinnae sometimes with 1- forked veins, hydathodes dark and sometimes slightly sunken. In contrast, X. parva possesses the smaller laminae and lobes with the rachis slightly prominent to prominent and slightly darker to darker on the abaxial surface and level to slightly sunken and concolorous to slightly darker on the adaxial surface, sterile pinnae with simple veins, hydathodes pale, not sunken. Zhang et al. (2013) regarded this species as X. devolii .

Additional specimens examined:— VIETNAM. Nha Trang Province: la Mère et l’Enfant, Poilane 5109, herb. C. Christensen (BM, image seen). Lam Dong Province: Lac Duong District, Da Chays Commune, Bidoup-Nui Ba National Park, Giang Ly Forest Station, 18 June 2013, Wade 2644 (SGN!, TAIF!). Quang Tri Province: Huong Hoa District, Bac Huong Hoa Nature Reserve, Huong Viet Commune, Ta Rung Village, km marker 0 along Ho Chi Minh Road from Sa Mu to Sa Mu top, 22 November 2014, L. B. Zhang, L. Zhang, N. T. Lu 7629 (VNMN!, CDBI, MO).

Figures

FIGURE 3. Xiphopterella parva—A. Habitat. B.Abaxial lamina. C.Adaxial lamina. D. Portion of adaxial lamina showing the distribution of hairs. Scale bars: A = 1 cm, B, C = 3mm, D = 3mm.