Monosolenium (Marchantiopsida) Penetrates the Paleotropics

Abstract

East Asian Monosolenium tenerum is the only representative monotypic Monosoleniaceae and has been found for the first time in North Indochina in five provinces of Vietnam. All paleotropical localities, including those previously known in Indonesia, are situated not in the high mountains, as one might expect for the East Asian species occurring southward in East Asia, but in the lower altitude zones (i.e., in conditions physiognomically similar to where the species grows further north). A comparison of the bioclimatic parameters of locations where the species was found revealed clear similarities across all the Vietnamese localities of the species. The closest bioclimatic location to where the species has been found in Vietnam is in Nepal. The species reaches its greatest abundance in anthropogenically nitrified habitats, which may suggest that it is currently expanding to southern Indochina along the rural settlements in the catchments of the largest rivers and suggests that it may be discovered in Cambodia, Laos, and southern Vietnam in the near future.

Keywords: East Asia; Hepaticae; Indochina; Monosoleniaceae; Southeast Asia; complex thalloid liverworts; distribution; rare species.

Figure 1

Scatter plot for the distribution of Monosolenium tenerum across bioclimatic parameters based on their collection localities across the area of the species according to Table S1. The numbers correspond to the number of Monosolenium tenerum specimens according to Table 1 (numbers from 14 to 19—specimens collected in Vietnam; the number 18 is coinciding with number 19 and cannot be shown in the scatter plot).

Figure 2

Monosolenium tenerum Griff.: (A,B) mat with female receptacles; (C) shoot with female receptacles; (D) shoot apex with female receptacles; (E,F) female receptacles; (G) mature sporangia in female receptacle; (H) female receptacle, spores from torn sporangium capsule. Scales: 10 mm for (A,B); 5 mm for (C); 3 mm for (D); 1 mm for (E–H). (A,B) from China-53-25-13 (VBGI), (C,E,F,H) from V-50-10-23 (VBGI, NH), (D) from V-18-7-23 (VBGI, NH), (G) from V-31-2-23 (VBGI, NH).

Figure 3

Monosolenium tenerum Griff.: (A) cross-section of the thallus; (B) cells in the middle part of the cross-section of the thallus; (C) cells in the ‘wing’ part of the cross-section of the thallus; (D) one layer of cells in thallus margin; (E) ventral scale; (F,G) cells of ventral scale. Scales: 500 µm for (E); 300 µm for (A,F); 100 µm for (B–D,G). All from V-50-9-23 (VBGI, NH).

Figure 4

Monosolenium tenerum Griff.: (A–D) cells of the thallus; (E) mature spores; (F–H) elaters. Scales: 300 µm for (A); 100 µm for (B,C); 50 µm for (E,F); 30 µm for (D). (A) from China-53-25-13 (VBGI), (B,D) from V-24-20-22 (VBGI, NH), (C) from V-18-7-23 (VBGI, NH), (E–H) from V-19-2-23 (VBGI, NH).

Figure 5

Dot distribution map of Monosolenium tenerum in Vietnam based on collected specimens. The numbers of localities correspond to Table 1 and Table S1.