Dryopteris pycnolepis Z. Y. Zuo & S. Y. Dong, 2025

Dryopteris pycnolepis Z. Y. Zuo & S. Y. Dong sp. nov.

Figs 1 C View Figure 1 , 3 View Figure 3 , 4 View Figure 4

Type.

Vietnam • Lào Cai Province: Sa Pa District, Mt. Hoàng Liên ; 22°18.47′N, 103°46.45′E; 17 June 2023; L. X. Zhou 16451 ( holotype, IBSC; isotypes: IBSC) GoogleMaps .

Diagnosis.

Dryopteris pycnolepis is very similar to D. sikkimensis but differs in its stipe and rachis very densely covered with large scales (versus obviously sparse, scattered scales) and the pinnules abaxially with long, fibrillose scales (versus pinnules glabrous).

Description.

Plants medium to large, 50–90 cm tall. Rhizome short, with fronds clustered on its apex; stipe 20–35 cm long (shorter than rachis), 2–3.5 mm thick, thickened at base (to 5 mm), lower portion (in basal 6–8 cm length from the base) dark brown, upwards stramineous, matte, together with rachis narrowly grooved adaxially and densely scaly except for the basal portion in dark brown (which bearing relatively few scales); scales dark brown or mostly blackish, lustrous, chartaceous, spreading acroscopically or laterally, polymorphic in size, smaller ones lanceolate, ca. 1.2 × 0.2 mm, larger ones or broadly lanceolate, 8–10 × 1.5–2.2 mm, apex acuminate or acute, base truncate or slightly cordate, margins entire or minutely erose; lamina herbaceous, adaxially dark green and abaxially pale green when living, oblong-lanceolate, 30–55 × 15–25 cm, bipinnate-pinnatisect, apex somewhat abruptly narrowed and acuminate, bearing 13–15 pairs of pinnae below the abruptly reduced terminal portion; rachis stramineous, densely scaly, with similar scales abaxially and linear or fibrillose scales (to 3–5 mm long) adaxially (the latter borne on rachis groove); pinnae linear or narrowly linear-lanceolate, spaced 5–8 mm apart except at base (where contiguous), subopposite or sometime those on upper rachis alternative, mostly patently spreading (with an approximately right anger to rachis) at base and distally curved toward frond apex, sessile, all pinnae (except those on terminal reduced portion of lamina) almost of the same size, with the lowest 1–2 pairs not or slightly shortened, middle pinnae 10–15 × 2–3 cm (with the widest base up to 4 cm wide), base asymmetrical, acroscopic base truncate (parallel to rachis and partly overlapping rachis), basiscopic base round or cuneate, apex acuminate, with copious, blackish, lanceolate scales on abaxial costae, the large pinna bearing 15–25 pairs of pinnules; pinnules generally alternative, obliquely spreading (forming an angle of ca. 50–60 ° to costa), nearly oblong, very shortly stalked, middle pinnules 1.8–2 cm long and 6–8 mm wide at base, acroscopic base truncate, basiscopic base round, apex obtuse, the acroscopic basal pinnule the longest (to 2.5 cm) and obviously longer than the second pinnule, pinnatisect, with fibrillose scales (ca. 5 mm long) on abaxial surfaces of costules and veins (fewer fibrillose scales present on adaxial surface); lobes of a middle pinnule 5–7 pairs, ascending, narrowly oblong, ca. 2.5–4.5 × 1.2–1.5 mm, apex round or obtuse, apiculate with 1–2 teeth, spaced ca. 1 mm apart; veins free, slightly visible on both surfaces, simple, once or twice forked, not reaching lamina margins. Sori round, confined to upper half of pinnules, 2–3 pairs per pinnule, one per segment, dorsal on the base of acroscopic veinlet, close to costules; indusia orbicular-reniform, large, ca. 1 mm in diameter, approximate to each other, margin entire, brown, membranous, persistent; spore reniform, monolete, ca. 32 × 16.5–18 µm, with smooth, glabrous surface of perispores.

Habitat.

Terrestrial alongside a trail in montane broadleaved evergreen forest, elevation 2860 m; currently only a small population observed in Mt. Hoàng Liên, northern Vietnam.

Etymology.

The specific epithet comes from the Latin words “ pycno - ” (densely bearing) and “ lepis ” (scales), referring to the scales densely borne on the stipe, and rachis.