Taxonomic revision of the genus Trismegistia (Pylaisiadelphaceae, Musci)

Abstract

The genus Trismegistia is a member of the Pylaisiadelphaceae (or Sematophyllaceae sensu lato) and can be distinguished from allied genera (Brotherella, Mastopoma, Pseudotrismegistia and Wijkia) by upright or obliquely ascending secondary stems with more or less developed stipes arising from prostrate primary stems; an often sharp differentiation in shape among stipe-, stem-, and branch leaves; distinctly bordered and mostly strongly serrate, dentate, or spinose leaf margins; strongly inflated, reddish brown alar cells of which the outer ones are segmented in several rows; setae up to 6 cm long, smooth; capsules mostly ovoid or short cylindrical, straight to weakly curved with superficial stomata; hypnoid peristome; and small spores. The genus is distributed in tropical Southeast Asia and some Western Pacific island groups. Nine species are recognized; T. brachyphylla M. Fleisch., T calderensis (Sull.) Broth., T. complanatula (Mull. Hal.) mall. Hal., T lancifolia (Harv.) Broth, T. malayana H. Akiyama, sp. nov., T. maliauensis H. Akiyama & Suleiman, T. p anduriformis (C.H. Wright) Broth., T plicata H. Akiyama, sp. nov., and T. spinosodentata (Zanten) H. Akiyama, stat. nov. Species with wide distribution ranges were divided into morphologically and geographically distinct infraspecific entities: two types of T. brachyphylla (Western- and Eastern-type), five varieties of T lancifolia (var. lancifolia, var. austlariana var. nov., var. everettii var. nov., var. pseudoplicata var. nov., and var. valetonii comb. nov.), three varieties of T calderensis (var. calderensis, var. rigida comb. nov., and var. subintegrifolia comb. nov.), and two varieties of T. panduriformis (var. panduriformis and var. prionodontella comb. nov.). The interrelationship among Mastopoma, Pseudotrismegistia, Trismegistia, and Wijkia is briefly discussed.