Caloglossa fonticola, Fang & Nan & Feng & Liu & Liu & Xie, 2021

Fang, Kun-Peng, Nan, Fang-Ru, Feng, Jia, Liu, Qi, Liu, Xu-Dong & Xie, Shu-Lian, 2021, Morphological and molecular evidence for the recognition of Caloglossa fonticola sp. nov. (Delesseriaceae, Rhodophyta) from an underground spring in Guangxi, China, Phytotaxa 522 (1), pp. 15-26 : 22-23

Caloglossa fonticola K.-P. Fang, F.-R. Nan & S.-L. Xie sp. nov. ( Fig. 2 )

Description —Thalli linear, dichotomously branched, pink to pale brown, attached to the rocks in a freshwater spring by clusters of rhizoids, about 1–2 cm high, consisting of a midrib region with monostromatic wings on either side ( Figs. 2 A-B). Midrib region composed of two transverse and two lateral periaxial cells, and one axial cell series, the length of axial cells in the mature thallus is 80–280 µm ( Figs. 2E–G ). Internodal regions or “blades” linear, rarely or slightly constricted at nodes, 1.5–5.0 mm long and 0.2–0.7 mm wide ( Figs. 2 A-B). At the node ( Figs. 2 C-D, 3), on the adjacent side to the lateral axis, all second- and third-order cell rows of the main axis reach the blade margin, the first axial cell produces 1–2 cell rows, 5–9 cells long. On the adaxial side, the first axial cell of the lateral axis produces only a second-order cell row usually only 2–4 cells long and not extending to the margin, the second and third axial cell produces one cell row, sometimes not extending to the margin. On the opposite to the lateral branch, the number of cell rows derived from nodal axial cell and the first axial cell of main axis are both two, which is the same as or one fewer than that in the internode region. On the abaxial side, the nodal axial cell produces only one row, 5–7 cells long usually not extending to the margin, the first four axial cells of the lateral branch produce two rows each, extending to the margin, by the sixth axial cell above the node the regular internodal condition is attained. At the internode ( Figs. 2E–G ), the inner 1–3 second-order cells produce third-order rows, thus on one side of the blade from any one axial cell the apical cells of 2–4 rows form the blade margin, with 5–10 cells per row to the margin. Rhizoids forming from groups of second and third-order cells which arise from the first three axial cells of the main axis and lateral axis, unicellular, 0.15–0.85 mm long, 20–30 µm in diameter, basal rhizoidal cells not tightly adherent to form a stipe-like cortical pad, each wing cell produces a single rhizoidal filament ( Figs. 2H–I , 3 ). Adventitious branches and endogenous branches both absent. Reproductive structures not found.

Diagnosis: ―Morphological characters as for Caloglossa bengalensis described in King & Puttock (1994) but differing in blade shape, degree of constriction at the thallus nodes, secondary branching pattern, the number of cells composing second-order cell rows at the internode, and the number of cells composing a single rhizoidal filament. Caloglossa fonticola is distinguished from other Caloglossa species by the following unique combination of character states: thallus internodal blades linear, hardly or slightly constricted at nodes, adventitious branches and endogenous branches both absent, and unicellular rhizoids forming from clusters of wing cells arising from the first three axial cells of the main axis and lateral axis. Diagnostic DNA sequence: rbc L and LSU accession numbers MW725289 and MW722975 , respectively.

Type locality: CHINA ― Guangxi, Bama County (24° 18′ 2″ N, 107° 5′ 58″ E, ASL: 260.5 m) . The spring water comes from Baimo Cave and is also the source of the Panyang River (WT = 21 ° C, pH = 7.79, DO = 6.66 mg / L, EC = 310 µS/cm, TDS = 218.4 mg / L) .

Holotype: Formalin-preserved specimen (SXU-GX19006) and herbarium voucher (holotype SXU-GX19010, isotype SXU-GX19011). December 2019, collected by Kun-Peng Fang.

Iconotype: Fig. 2

Etymology: fonticola from the Latin “of the spring,” named for the freshwater system the species inhabits.

Figures

FIGURE 2. Morphological structures of Caloglossa fonticola sp. nov. A. Vegetative thalli of C. fonticola. B. Thallus blades showing hardly or slightly constricted at nodes, and lateral axis (arrows) demonstrating significantly less growth than the main axis (arrowheads). C. Cell arrangement around a node. Nodal axial cell (diamond) and first axial cell (star) of the main axis (MA) both produced one secondorder cell row (arrows) and one third-order cell rows (arrowheads) on the opposite to the lateral branch (LA), all these cell rows reach to the blade margin. D. Nodal region of thallus illustrating the nodal axial cell (diamond) produces one cell row (arrowhead) on the abaxial side not extending to the margin, and the first axial cell of the lateral axis (asterisk) produces one cell row (arrow) on the adaxial side not extending to the margin. E-G Internodal blade. Each axial cell (a) produces one second-order cell row (arrows) that forms 1-3 third-order cell rows (arrowheads). H. Rhizoids at node showing each wing cell produces a single rhizoidal filament (white arrowheads). I. Rhizoids at node displaying the type B arrangement of Kamiya et al. (2003). Rhizoidal filaments (arrowheads) arising from wing cells near the main axis and lateral axis at the nodes. Scale bars: A = 1 cm, B = 1.0 mm, C and E = 200 μm, D, F and G = 20 μm, H and I = 100 μm.

FIGURE 3. Drawing of Caloglossa fonticola sp. nov. thallus at the node follows Kamiya et al. (1999, 2003). Transverse pericentral cells are omitted. Axial cells are brown, wing cells are purple, and rhizoids are cyan. AB, abaxial side; AD, adjacent side to the lateral branch; AX, adaxial side; FLA, first axial cell of the lateral axis; FMA, first axial cell of the main axis; LA, lateral axis; LPC, lateral pericentral cell; MA, main axis; NA, nodal axial cell; OP, opposite side to the lateral branch; WC, wing cell; Rhizoids form from groups of second and third-order cells arising from the first three axial cells of the main and lateral axes (type B in Kamiya et al. 2003). Scale bar = 200 µm.