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Patterns of Sporophyte Maturation Dates in the Pottiaceae (Bryopsida)

1979; American Bryological and Lichenological Society; Volume: 82; Issue: 4 Linguagem: Inglês

10.2307/3241994

1938-4378

Richard H. Zander,

Peatlands and Wetlands Ecology

Patterns of sporophyte maturation dates (SMDs) in the Potti- aceae correlate with sexual condition, latitude, date of regional precipitation maximum, habitat and taxonomic group. Most closely related species have SMDs at about the same time (at the month or season level of resolution), but many species complexes, sections, genera and suprageneric taxa have distinc- tive SMDs that may be used as taxonomic characters. An eurychronic group of mostly dioicous, largely hygrophilic species shows a relatively great dif- ferentiation of SMDs between geographic regions. A review of the literature on sporophyte maturation dates (SMDs) in taxa of the Pottiaceae was undertaken to determine its possible taxonomic value. Major floristic studies of the Bryopsida, since the time of-Hedwig, commonly give the season or month(s) of sporophyte capsule maturity as part of the species description, yet seldom is this characteristic used in distinguishing taxa. Near the turn of the century, several studies (Arnell, 1875, 1905; Grimme, 1903; Krieger, 1915) of moss phenology sought to compare dates of sporophyte maturation in taxa but were handicapped by the small number of species for which information was known. Since then, many floristic studies have included phenological information, and this paper summarizes the data on the family Pottiaceae given in 10 major floristic manuals concerning widely scattered areas of the North Temperate Zone of both Old and New Worlds. The probable intent of early authors was to provide data for mosses comparable to times of anthesis in flowering plants. However, because syngamy in mosses occurs up to one year or more before the date of capsule dehiscence, while in angiosperms it occurs just after anthesis, information about sporophyte maturation dates cannot be directly used to estimate degree of temporal reproductive isolation of taxa by different fertilization times. As has been emphasized by Forman (1965), Greene (1960) and Scott et al. (1976), species-specific variations in time of fertilization and of SMD have been described for relatively few mosses. Forman (1965) and Greene (1960) suggested notational systems for recording phenological stages of the life cycles. Previous large-scale studies comparing times of fertilization and of sporophyte maturation have dealt with only a few species of each of many families of mosses and involve only one or two floristic regions. Grimme (1903) compared Arnell's (1875) data from Scandinavia with that given by Limpricht (1890-1894) for Germany, Austria and Switzerland and found that sporophyte development in German mosses usually took a longer time than did Scandinavian mosses of the same species. Fertilization occurred one or two months earlier in Germany. This was apparently related to the longer growing season of the southern areas. He also concluded from his own obser-