ADDRESSING THE THEORETICAL FRAMEWORK:     Mitthyridium:  taxonomy, history, and previous study.  Mitthyridium is known exclusively from the paleotropics (Reese, 1993c), and was partially revised by Nowak (1980), who included keys, descriptions, illustrations, and distribution maps in her valuable treatment.  More recently, Reese et al. (1986b) provided a thorough synopsis of Mitthyridium as it occurs in Malaysia and adjacent islands.  The group appears to be monophyletic, but is taxonomically difficult at inclusive levels, since circumscriptions of species are weak, debated, and often changed (Reese et al., 1986a-b; Reese et al., 1994; Reese, 1994a).  Still, relatively few species, within four subgenera (Reese, 1994a), have been described for this genus (Table 1), especially in relation to its huge sister genera, Calymperes and Syrrhopodon.  This relative lack of species descriptions may be attributed to Mitthyridium's confinement to the paleotropics which relatively few studies have targeted (e.g., Allen, 1987; Bartam, 1933a-b; 1936; 1939; 1940; 1945; 1950; 1951; 1956; 1957a-b; 1960a-c; 1961; Brotherus, 1924; Dixon, 1916; 1924; 1932; 1935; Dixon and Greenwood, 1930; Eddy, 1988; Menzel and Schultze-Motel, 1990; Nowak, 1980; Touw, 1971; 1978; 1974; 1992; Schultze-Motel, 1963; Tixier, 1966; Whittier, 1976; Whittier and Whittier, 1987).
    Indeed paleotropical exploration of bryophytes has lagged behind that of neotropical and temperate regions.  Recent explorations by Dr. Mishler and myself have added more than 20 species to previously published lists from French Polynesia (Whittier and Whittier, 1976; DeSloover, 1993).  Whittier and Whittier (1987) report and others conclude similarly (Schultze-Motel, 1982; Touw, 1974) that: "1) floristic exploration [of the paleotropics] remains far  [italics theirs] from complete, and becomes increasingly urgent with explosive population growth and housing development with concomitant agricultural/forestry expansion; that 2) further monographic research is acutely needed to resolve nomenclatural, systematic and biogeographic problems ..."  Although many authors have done and continue to do pivotal work on paleotropical bryology (e.g., Norris and Koponen, 1985a-b; 1987; Norris et al., 1988; Menzel and Schultze-Motel, 1990; Nowak, 1980; Miller et al., 1963; 1978; Reese et al. 1986a-b; Touw, 1971; 1974; 1978; 1992), understanding of the bryo-flora for the paleotropics remains incomplete.  Clearly more explorations, collections, and extensive analyses are needed.