Virescentia guangxiensis FANG, NAN and XIE

Guo, Wei-Nan, Nan, Fang-Ru, He, Zhong-Shi, Liu, Xu-Dong, Liu, Yang, Liu, Qi, Feng, Jia & Xie, Shu-Lian, 2025, Morphology and molecular phylogeny of Virescentia guangxiensis (Batrachospermaceae, Rhodophyta), Phytotaxa 687 (1), pp. 84-100 : 92-93

Virescentia guangxiensis FANG, NAN and XIE , emend. nov. ( FIGURE 1 and FIGURE 2 )

Revised description: gametophyte thalli monoecious or dioecious, olive green in colour, abundantly or moderately mucilaginous, 2–3 cm high, branching irregular. Whorls well-developed, contiguous or separated, barrel-shaped or spherical, 250–425 mm in diameter, internodes 125–300 mm in length, axial cells colourless, sometimes brown, 20– 40 mm in diameter. Cortical filaments abundant, with only cylindrical cells, 6–12 mm in diameter, 26–39 mm or longer. Primary fascicles straight, consisting of 4–7 layers of cells, dichotomously branched, 2–3 times branched. Proximal cells are cylindrical or barrel-shaped, 26–40 µm long and 6–10µm in diameter and distal cells oval obovoidal and 5–8µm in diameter. Secondary fascicles abundant, covering the entire internode, unbranched or dichotomously branched, shorter or as long as the primary fascicles. Terminal special expansion cell on primary or secondary fascicles, obovoidal, 15–25 µm in diameter, 27–34 µm in length, or spherical, 12–25 µm in diameter. Spermatangia spherical or sub-spherical, single or in pairs, 6.5–9.0 µm in diameter. Carpogonia 38–70 µm in length with pedicellate and club-shaped trichogynes, 6–10 µm in diameter. Carpogonial branches helically twisted, arising from pericentral cells, composed of 6–8 cells. Carposporophytes semiglobose, sparse, one per whorl, lower than whorls. Carposporangia obovoidal shaped, 17–27 μm long and 14–18 μm in diameter.

Uniseriate (‘Chantransia’) thalli small, greenish in color, 2–4 mm high and the base consists of an irregular prostrate filament system. Vegetative cylindrical, 16.98–83.98 μm long, 9.07–12.18 μm in diameter, vegetative fascicles branch angles ≤ 25°, irregularly lobed chloroplasts. Monosporangia small and abundant, ovoidal or sub-spherical, 11.56–17.48 μm in length, 7.60–12.21 μm in diameter.

Specimen information: the sample SXU-ZJ23003 was collected from Hangzhou City, Zhejiang Province, China on 7 April, 2023, by WZU and GRZ. Diagnostic DNA sequence: rbc L and COI (accession number: OQ941782 for rbc L and OQ941783 for COI). The sample SXU-SX23004 was collected from Linfen City, Shanxi Province, China (36°17′10.4″N, 111°45′12″E,ASL: 498.6 m) on 12 October, 2023, by GWN and WCH, growing in spring water attached to stone (WT=14.7 ℃, pH=7.11, DO= 8.48 mg /L, EC=1443 μs/cm, TDS= 939 mg /L, SAL=0.73ppt). Diagnostic DNA sequence: rbc L and COI (accession number: OR709673 for rbc L and OR709674 for COI). Diagnostic chloroplast genome accession number: OR885128 and mitochondrial genome accession number: OR885129. The liquid immersion specimens (SXU-ZJ23003 and SXU-SX23004) were deposited in the Herbarium of Shanxi University (SXU), Shanxi University, Taiyuan City, Shanxi Province, China. April and October 2023 by Wei-Nan Guo.

Distribution: China--Hechi, Guangxi Province; Nanyang, Henan Province; Hangzhou, Zhejiang Province; Linfen, Shanxi Province.

Figures

FIGURE 1. Morphological characteristics of V. guangxiensis (Zhejiang provinces, China, Gametophyte sample SXU-ZJ23003). A. Olive green thalli; B. Secondary fascicles abundant, covering the entire internode; C. Main axis with dense spherical-shaped whorls containing semi-globose and unstalked carposporophytes (arrow); D. Fertilized carpogonium with cylindrical trichogyne (arrow) and attached spermatatangia (double arrowheads); E. Mature carpogonium with pedicellate trichogyne (arrow) and carpogonial branches helically twisted, arising from pericentral cells (double arrowheads); F. Location in the terminal special expansion cell of primary or secondary fascicles.

FIGURE 2. illustrates the morphological features of the SXU-SX23004 strain, isolated from Linfen City, Shanxi Province, China. This sample has olive-green erect filaments, ovoid or sub-spherical monosporangia characterized by branching angles ≤ 25°, and irregular lobed chromatoplast.