Selaginella parachrysocaulos, a new record to Guizhou, China

Fig. 7

Selaginella parachrysocaulos M. H. Zhang & X. C. Zhang, Taxon 71: 1167. 2022.

Type.

China • Sichuan: Miyi County, elev. 1600–1800 m, in forest, 10 September 2002, X. C. Zhang 2427 (holotype, PE, barcode 02347433).

Description.

Plant erect, 7–30 cm, with tuber and stolon at base, tuber covered by colourless scale-like leaves; rhizophores restricted to base of main stem; main stem branched from middle or lower part, terete, glabrous, stramineous, 0.6–1.3 mm in diam. at basal part, 4.0–8.0 mm wide including leaves; primary branches alternate, 5–10 pairs, 0.5–1.8 cm apart along the main stem, once or twice pinnately branched, with ultimate branches including leaves being 3.0–5.0 mm wide; vegetative leaves herbaceous or slightly membranous, dimorphic, arranged in four rows, with obvious white margin; axillary leaves symmetrical, ovate-lanceolate or narrowly triangular, 2.0–2.6 × 0.7–1.2 mm, base rounded, apex acuminate, margin denticulate to shortly ciliolate; median leaves slightly asymmetrical, ovate, 0.8–1.4 × 0.4–0.8 mm, base cordate, 1.6–2.8 × 0.6–1.5 mm, apex aristate, margin shortly ciliolate; lateral leaves asymmetrical, ovate-lanceolate, 1.8–3.2 × 0.8–1.8 mm, base rounded, with acroscopic base slightly enlarged, acroscopic margin shortly ciliolate at base and denticulate towards apex, acroscopic margin denticulate; strobili solitary or pairs, terminal on the branches, compact, dorsiventrally complanate, 3.3–5.8 × 2.3–3.4 mm; sporophylls strongly dimorphic, resupinate, obvious white-margined; dorsal sporophylls ovate-lanceolate, with sporophyll-pteryx complete and shortly ciliolate, 1.6–2.1 × 0.4–0.6 mm, base rounded, apex acute, margin denticulate to shortly ciliolate; ventral sporophylls ovate-lanceolate, slightly carinate, 1.4–1.9 × 0.4–0.8 mm, bases rounded, apex long acuminate, margin denticulate to shortly ciliolate; megaspores yellowish, subglobose, both proximal and distal surfaces verrucate, surfaces densely covered with fine spines; microspores orange, tetrahedral-globose, surface verrucate, covered with honeycomb-like microsculpture on the surfaces.

Distribution and habitat.

Endemic to south-western China (Guizhou, Sichuan, Yunnan); growing on ground or rocks in forests at 1600–3100 m elev. The Guizhou population was found on wet cliffs in montane evergreen broad-leaved forest at 1855 m elev.

Notes.

The collection D 6641 documents the first record of S. parachrysocaulos in Guizhou, China. This species is morphologically similar to S. chrysocaulos, but differs by the slightly enlarged acroscopic base of lateral leaves (vs. strongly enlarged) and the honeycomb-like sculpture on microspore surface (vs. smooth in S. chrysocaulos) (Zhang and Zhang 2022). Notably, during examination of spore morphology in specimen D 6641, we observed that the microspore surface sculpture is variable. In some microspores, a distinct honeycomb-like pattern is evident, whereas in more well-developed microspores, it appears obscure or only partially visible. This suggests that the honeycomb-like sculpture may gradually diminish as the spores reach full maturity in S. parachrysocaulos.

Voucher specimen from Guizhou, China.

• Qishe, Xingyi, 24°57'09"N, 104°45'10"E, elev. 1855 m, 3 August 2024, S. Y. Dong, J. K. Huang & X. J. Li D 6641 (IBSC).