Introduction The biogeography of ferns and lycophytes can be studied from several points of view and with various methods. It might, for instance, examine the distribution of species on a single tree (Kromer and Kessler, 2006; Schuettpelz and Trapnell, 2006), or the frequency and abundance of species over large regions (Ruokolainen et al. , 1997; Lwanga et al. , 1998; Tuomisto et al. , 2003; Jones et al. , 2005; Tuomisto and Ruokolainen, 2005), or the relationships of species on different continents (e.g., Moran and Smith, 2001; Parris, 2001). Methods can be as varied as producing lists of plants growing on different soil types (e.g., Young and Leon, 1989; van der Werff, 1992), calculating the percentage of floristic similarity between different regions (Dzwonko and Kornas, 1978, 1994; Pichi Sermolli, 1979), or analyzing the phylogeny of a clade in relation to its geography and geological history (e.g., Geiger and Ranker, 2005; Hoot et al. , 2006). These and other approaches have contributed to what is now an overwhelming amount of literature on the subject. To limit the subject for this chapter, three themes have been chosen: diversity, long-distance dispersal, and vicariance. After discussing these, a summary of the current state of floristics is given because biogeography is ultimately based on that subject. Historical review The earliest works on fern and lycophyte biogeography were mostly tabular summaries of the percentages and/or occurrences of species in different regions of the world (D'Urville, 1835; Baker, 1868; Lyell, 1879).

Biology and Evolution of Ferns and Lycophytes: Diversity, biogeography, and floristics

Key points 1. Biogeographical patterns of ferns and angiosperms are the result of a combination of vicariance and long distance dispersal, but due to their more effective dispersal via spores, the latter is more frequent among ferns. Therefore, fern species tend to have wider ranges and the relative number of fern species compared with seed plants is highest on remote, mountainous tropical islands such as Hawaii and the Mascarenes. Also, fern communities on different continents are more similar compositionally than those of seed plants. 2. Despite their potential for long distance spore dispersal, many fern species have localized ranges as a result of low frequency of successful long distance dispersal, habitat specialization, geographical isolation and competitive interactions between species. 3. Species richness of ferns follows a latitudinal gradient that peaks in the tropics, where ferns are especially diverse and abundant in wet habitats with moderate temperatures at elevations of about 1000–2500 m. On average, species in tropical mountains have elevational amplitudes of about 1000 m. The peak of endemism is located at higher elevations than that of species richness. Introduction Biogeography deals with the distribution patterns of species and communities, and their causal relationships with factors such as climate, soil and evolutionary history (Humboldt, 1805; Lomolino et al ., 2006). Specific topics addressed by biogeographers include the sizes of geographical ranges and their spatial placement, the way individual species attain their distribution ranges (dispersal, extinction and vicariance), the distribution of species numbers (alpha diversity), changes in species composition (beta diversity) and the spatial distribution of species traits (macroecology).

https://www.zora.uzh.ch/id/eprint/42711/1/Kessler_Fern_Ecology_Book_2010.pdf

Biogeography of ferns

Cell division patterns in germinating spores of several Thelypteris species were studied using light microscopy of sectioned material and scanning electron microscopy. All species exhibited the same basic germination pattern, characterized by an asymmetric cell division of the spore parallel to the equatorial plane to delimit a proximal rhizoid, followed by a perpendicular division of the basal cell to form the protonemal cell. While spore-germination patterns appear to be a potentially useful taxonomic character in some groups of ferns, the homogeneity in this character exhibited by the thelypteroid group impairs its usefulness in the taxonomy of The-

The spore-germination pattern of thelypteroid ferns

Developmental gametophyte morphology of seven species of Thelypteris subg. Cyclosorus (Thelypteridaceae)

Spores of six Chinese species of Pteris (Pteridaceae) were sown on soil and subsequent gametophyte morphology and development were studied. Spores of all species are trilete, tetrahedral and with a distinct equatorial flange. Germination is Vittaria-type and the prothallial development is Ceratopteris-type in all of the species. Adult gametophytes are cordate and gametangia are of the common type for leptosporangiate ferns. Differences among species include spore size, germination time, formation time of the gametangia, gametophyte margin shape, number of archegonial neck cells and shapes of the antheridial dehiscence.

https://bioone.org/journals/American-Fern-Journal/volume-98/issue-1/0002-8444(2008)98[33:GMADOS]2.0.CO;2/Gametophyte-Morphology-and-Development-of-Six-Chinese-Species-of-Pteris/10.1640/0002-8444(2008)98[33:GMADOS]2.0.CO;2.pdf

Lenette R. Atkinson

Papers

The gametophyte of some Jamaican thelypteroid ferns