n = 9. Figs. 11-15, 61g-i.
Hypnodendron vitiense in subgenus Hypnodendron, a widespread species in the Australasian region, is considered to consist of two weak subspecies (Touw, 1971). He suggested northeast Queensland as a transitional area where both subspecies occur, but plants in this area are depauperate and sporophytes have not been found there yet. The subspecies australe examined in these studies occurs primarily in southeastern Australia: New South Wales, Australian Capital Territory, Victoria and Tasmania; but it has been collected, although less frequently, in Queensland as far north as the Caims District.
The chromosome number n = 9 (from meiotic and mitotic counts) was first reported for H. vitiense subsp. australe by Ramsay (as H. arcuatum, 1966, 1967, 1974; also mentioned in Scott & Stone, 1976). Two further collections, one from New South Wales the other from Victoria (Table I, Appendix I), confirm the number as n = 9 (Figs. 11, 12). The two populations studied, from diflferent states, showed some diflference in bivalent size between them (cf. Figs. 11 & 12). Alignment of the bivalents (Fig. 13) separates them into four large, two intermediate and three smaller ones. Early separation of one small bivalent was noted, which might be considered an m-bivalent (Fig. 61 i). Ramsay (1974) studied both premeiotic (In = 18) and gametophytic mitotic (n = 9) chromosome complements. The aligned chromosomes are redrawn here as Figs. 14 and 15 for comparison with other species. The largest chromosome was metacentric in the gametophytic complement but the two largest chromosomes in the sporophytic complement appeared to diflfer, one being submetacentric. As the species is dioicous, this m ay reflect some sex diflferences, possibly of the structural kind as no dimorphic bivalent was observed. However, the large bivalent behaved diflferently from others in the complement (Fig. 61g, h) a feature which might be considered a "sex-bivalent" in some mosses (Ramsay, 1983b). Evidence from male material is required before this suggestion can be tested.