Hymenasplenium laterepens N.Murak. & X.Cheng ex Yanfen Chang & K.Hori, 2018

Chang, Yanfen, Hori, Kiyotaka, Murakami, Noriaki, Cao, Limin, Lu, Shugang & Schneider, Harald, 2018, Validation of Hymenasplenium laterepens (Aspleniaceae): evidence from morphology and molecular analyses, Phytotaxa 374 (4), pp. 277-290 : 284-285

Hymenasplenium laterepens N.Murak. & X.Cheng ex Yanfen Chang & K.Hori , sp. nov ( Figs. 5 , 6).

Type:— CHINA. Yunnan: Xishuangbanna, Mengla County, Bubeng, elev. 580 m, in soil or on rocks near streams in shaded forests, April 15 2016, Yan-Fen Chang & Hua-Feng Hong, Chang 1039 (holotype, HITBC!, isotype, KUN!).

Plants 25–40 cm tall. Rhizomes long creeping, 2–3.5 mm in diameter, apex densely scaly; scales dark brown, narrowly triangular, entire; phyllopodia distinct, ca. 2 mm tall, 2–3 mm apart. Fronds grayish green, herbaceous; lamina onepinnate, ovate-triangular, 10–25 × 5–8 cm, widest near base, gradually narrowing toward apex, apex acute, glabrous; stipe shiny, purple to black, 10–25 × 0.05–0.15 cm, glabrous, base sparsely scaly; rachis shiny and purplish black abaxially, adaxial side grooved and with two grayish green narrow wings; pinnae almost sessile to shortly stalked with rachis color extending via the foot-stalk of the pinnae onto base part of costa abaxially, 10–25 pairs, alternate, spreading with basal pairs deflexed near stipe, quadrangular-trapeziform, 3–4.2 × 0.7–1.2 cm, base asymmetrical, acroscopic side truncate and parallel to rachis, subauriculate, basiscopic side attenuate-cuneate, with ca. 1 ⁄ 3 cut away, acroscopic margin serrate, teeth not retuse, pinna apex subacute. Veins forking and terminating in marginal teeth, only one or two basal basiscopic veins lacking. Sori linear, 3–6 mm, medial; indusia brownish, linear, membranous, entire, opening toward costa. Spore with crests. Plants triploid, likely apogamous, with chromosomes 2n= ca. 117.

Diagnosis: Hymenasplenium laterepens is similar to H. apogamum (N.Murak. & Hatan.) Nakaike. However , H. laterepens has larger triangular lamina, pinnae acute at the apex and more deeply serrated on the margin, and long creeping rhizome with thicker roots.

Distribution and habitat: H. laterepens is currently known to coexist with H. apogamum in southeastern China in soil or on rocks near streams in shaded forests at elevation of 200– 800 m.

Specimens examined (paratypes): — CHINA. Yunnan: Mengla County, Bubeng, May 11 2015, chang991, chang1134, chang1153, chang1154, chang1155, chang1156, chang1157, chang1158, chang1159 ( HITBC). Guangxi: Shangsi County, Shiwandashan, June 7, 2015, Yanfen Chang, chang 1160, chang1161, chang1162, ( HITBC).

Figures

FIGURE 5. Hymenasplenium laterepens—A: habit; B: plant; C: long creeping rhizome; D: Adaxial surface of pinnae in middle part of leaf; E: Abaxial surface of pinnae in middle part of leaf; F: spore. Scale bars: A=10 cm; B=2 cm; C–E=1 cm; F=10 μm.