Ectropothecium falcatulum (Broth.)

Yi, Zhao-Qin, Mu, Li-Qiang & Jia, Yu, 2022, Notes on Glossadelphus M. Fleisch. (Hypnaceae, Bryophyta) in China, Phytotaxa 541 (3), pp. 225-239 : 232-233

3-2. Ectropothecium falcatulum (Broth.) Z.-Q. Yi & Y. Jia, comb. nov. ( Figs. 4 , 5 A–H )

Glossadelphus falcatulus Broth., Symb. Sin. 4: 121. 1929. Type:— CHINA. Yunnan: In pluviisilvis mixtis calide temperatis prope vicum Bahan ( Pehalo ) ad fluvium Lu-djiang ( Salween ) 27°58’, in lapidibus irrigatis. 2400–2600 m, 24 June 1916, Handel-Mazzetti 9091 (lectotype, designated here: WU [ WU0046480 ]!) .

Plants medium sized. Stems creeping, irregularly branched; central strand present. Pseudoparaphyllia complex, mixed with filamentous and foliose ones, usually 2-cells wide at base and filamentous above. Stem and branch leaves somewhat similar in size and shape; leaves of dorsal, ventral and lateral surfaces differentiated. Dorsal leaves triangle, complanate, 0.9–1.1 × 0.4–0.5 mm. Ventral leaves widely ovate-lanceolate at base and abruptly becoming narrow upwards, slightly falcate, 0.85–1.0 × 0.5–0.55 mm. Lateral leaves lanceolate, obviously concave, falcate-secund, 0.75–1.2 × 0.45–0.5 mm. Leaf apices acute. Leaf margins of upper dentate with single teeth; costae double, usually unequal in length, 1/4 to 1/3 of the leaf length. Laminal cells linear, thin-walled, projecting at upper end; median cells 75–80 × ca. 4 µm; alar region distinctly differentiated with less than 5 short rectangle cells and a large, hyaline cell at each base of leaves. Asexual reproductive bodies not seen. Dioicous, only see the perigonium. Sporophytes not seen.

Habitat:—On wet limestone rocks near a stream.

World distribution:— China [Yunnan].

Other specimens examined:—Only known from one type specimen.

Comment:— Glossadelphus falcatulus was published in 1929 as an endemic species to China ( Brotherus 1929b). Later, Tixier (1988) treated it as a synonym of Ectropothecium kerstanii Dixon & Herzog in Herzog (1939: 96) without any comments. Our examination of type materials of G. falcatulus and E. kerstanii indicates that both species should be placed into Ectropothecium just as Tixier’s (1988) treatment on them. However, evident morphological differences between the two species are observed. For example, E. kerstanii is a robust plant with very densely arranged leaves, while G. falcatulus is a medium-sized plant with slightly loosely arranged leaves. Additionally, G. falcatulus differs from E. kerstanii in smaller leaves (0.8–1.1 × 0.4–0.5 mm vs. 1.5–1.7 × 0.8–0.9 mm), triangle dorsal leaves (vs. broadly ovate), oblong-lanceolate lateral leaves (vs. wide lanceolate), and alar regions slightly differentiated, with less than five short rectangular cells (vs. alar regions clearly differentiated, with 10–15 sub-square cells). In conclusion, G. falcatulus and E. kerstanii represent two different independent species. Here, we propose to treat G. falcatulus as an independent species of Ectropothecium , and make a new combination, E. falcatulum (Broth.) Z.-Q. Yi & Y. Jia.Among all Chinese Ectropothecium species, E. falcatulum resembles E. ohosimense Cardot & Thér. in Thériot (1908: 251) but the latter is different in having denser and shorter branches and shorter setae.

Figures

FIGURE 4. Ectropothecium falcatulum. plants, from lectotype of Glossadelphus falcatulus.

FIGURE 5. Ectropothecium falcatulum and E. kerstanii. A, I: Plants; B, J: Branch leaves (B1–B2, J1: Dorsal leaves; B3–B6, J3–J6: Lateral leaves; B7–B8, J2: Ventral leaves); C: Marginal and adjacent laminal cells; D, K: Pseudoparaphyllia and primordia; E, L: Leaf apices; F, G, O, P: Basal laminal cells; H, M: Cross-section of stems; N: Median laminal cells. A–H, from lectotype of Glossadelphus falcatulus. I–P, from isotype of E. kerstanii (S-B70441). Scale bars: a for A, I; b for B1–B8; c for C; d for E–H, L–M, O; e for J1–J6; f for D, K, N; g for P.