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In many ways, it is presumptuous for me to speak on the mosses of the tropical regions of China. Many consider the knowledge about the taxonomy, ecology, and geography of tropical bryophytes inadequate (Pócs 1982; Schuster 1983; Richards 1984), and this is certainly the case for the bryophytes of the tropical regions of China. The taxonomy of Chinese taxa is generally in a state of disarray. Early workers, both Chinese and others, have tended to describe new species based upon minor or inconsequential morphological characters and without apparent reference to related taxa found outside of China. This is clear from recent monographic studies that compared Chinese taxa with taxa throughout the world.
Of the 65 species of Campylopus known from tropical America, 33 are andine in distribution, 16 are found only in SE Brazil, 8 have wide ranges through Central and South America, 3 species are disjunct in SE-North America and Brazil, 3 are confined to the Caribbean and one species belongs to the circum-pacific and one to the tethyan element. For different parts of the Neotropics, the composition of phytogeographical elements is calculated. For the first time, bryophyte distributions are compared to the Pleistocene forest refuges proposed by zoologist and phanerogamists. The distribution of several rainforest species of Campylopus coincides with the major part of the montane refugia. Using an interpretation of the present-day ranges, a hypothetical survey is given of the origin and evolution of this genus in tropical South and Central America. The ranges of part of the species can be explained only by long distance dispersal, while the ranges of other species seem to be relictual.
During the past 5 years intensive bryological explorations were carried out in Tanzania with special emphasize on hitherto undercollected areas (e.g. Nguru mountains, Mafia Island, unknown accesses of Mount Kilimanjaro and Meru) and on special habitats (e.g. rocky semi-desert or heath vegetation and alkaline tolerant epiphytic vegetation along the Rift Valley). These collections (above 8000 numbers) resulted in numerous records, some of them new to the African continent and at least 8 species new to science. The data point to interesting phytogeographical links and help to explain the evolution of the flora of East African volcanoes and crystalline mountains. Hitherto unknown oil bodies of more than 50 liverwort species were investigated. This paper does not give a full account of these studies but only provides examples to illustrate the above points.
The Guianas (French Guiana, Suriname, Guyana) are probably one of the last areas of the world covered largely by virgin lowland rain forest. Species diversity of epiphytic bryophytes was investigated in dry evergreen forest and mixed forest using mountaineering techniques to ascend into the canopy. The results indicate that the lowland rain forest is richer in species than previously believed due to neglect of the canopy flora, which may hold more than 50% of the local species. The mixed forest holds the richest flora and on one single forest tree up to 67 bryophyte species were found (50 on average); 28 trees yielded 154 species. A species/area curve indicates that epiphytic bryophyte species are usually commonly distributed in the forest and a few trees may yield much of the local flora. A recent checklist of the Guianas includes over 600 species of bryophytes: 375 Hepaticae and 234 Musci. As the region lacks in altitude (except on Mt. Roraima) the general character of the bryophyte flora of the Guianas is typically lowland neotropical. Over 80% of the species are rather widespread in tropical America (Amazonian species included), and the remaining are Guayana Highlands, northern Amazonian or Caribbean elements. Endemism is very low: 2.5 %.
The neotropical hepatic flora, predominantly constituted by members of the Jungermanniales and Metzgeriales, includes a disproportionate number of genera which are endemic (over 38) and a number which evidently originated here but have shown slight and in a geological sense, modern dispersal by solitary species. Endemism is confined almost to the Jungermanniales; it is to a large degree of a unique sort: confined to highly apomorphic derivatives, often extremely reduced, sometimes confervoid or thalloid (aside from 'normal' sexual branches). These endemics are derivatives of basically cool-Gondwanalandic suborders, chiefly Lepidoziineae and Cephaloziineae which, in the Antipodes today include a wide range of plesiomorphic taxa. The highest proportion of endemic genera, often stenotypic (1-3 species each) occurs in the upper montane zone: from upper Andean forest to páramo, to the edge of permanent snow and ice; a smaller number occurs at upper elevations of the Guyana Shield, but more occur in the riverine systems that dissect this shield. The taxa found there (i.a., Zoopsidella, Pteropsiella, Schusterolejeunea, Cephalantholejeunea) are among the most apomorphic of all hepatics. The amount of endemism is shown to be higher than in any comparable region of the globe. It is assumed that this is owing to: (a) isolation, exceeding 40 m.y. and probably exceeding 60 m.y.; (b) continuous tectonic activity, preserving the 'raw' and 'pioneer' habitats which are necessary for the survival of 'fugitive', 'shuttle' and other types of pioneer taxa; (c) the antiquity of the Guyana Shield and its riverine system; (d) creation of striking ecological gradients, many biotic islands; (e) fluctuation in extent and degree of isolation of these 'islands', leading to (f) rapid evolution due to genetic drift and perhaps enhanced selection pressures. It is concluded that part of the complexity of the flora is due to preservation of some elements on the old Guyana Shield but most is due to relatively rapid evolution during Tertiary times. A final contributing element has been the fact that movement of the South American plate has been primarily from east to west, so that the relevant land area has not been rafted into regions with very different climatic parameters: the degree of extinction seen in, e.g., India and Australia is not evident here. It is concluded that the amount of endemism seen, and its extreme kinds, 'need' in excess of the 40-60 m.y. time span which seems available. In particular, the large number of high elevation endemics, some (such as Ruizanthus) very isolated, cannot be satisfactorily explained by assuming their evolution in the few million years available since alpine regions were created by the rise of the Andes. It is almost necessary to conclude that limited 'pre-Andes' must have existed and that the ancestors of the isolated taxa seen today in alpine loci in Colombia and Venezuela originated elsewhere. The other side of the outlined scenario is that with the near-total isolation of tropical America until the Andes were elevated, and until the Pliocene connection to North America arose, one would expect to see few and scattered intruders from cool-Gondwanalandic areas and from Laurasia. The modern flora reflects exactly this.
A floristic and ecological study of bryophytes and macrolichens in different lowland rain forest types around Mabura Hill, Guyana, South America, yielded 170 species: 52 mosses, 82 liverworts and 36 macrolichens. Lejeuneaceae account for about 30% of the species and are the dominant cryptogamic family of the lowland rain forest. Special attention was paid to the flora of the forest canopy, by using mountaineering techniques. It appeared that 50% of the bryophyte species and 86% of the macrolichens occurred exclusively in the canopy. Dry evergreen 'walaba' forest on white sand is particularly rich in lichens whereas the more humid 'mixed' forest on loamy soil is characterized by a rather rich liverwort flora. More species are exclusive to the mixed forest than to dry evergreen forest due to the 'canopy effect', i.e. the occurrence of xerophytic species in the outer canopy of both dry and humid forests. Furthermore, canopy species have wider vertical distributions on trees in the dry evergreen forest than in the mixed forest, due to the more open canopy foliage of the dry evergreen forest.
Based on a study of ca. 120 Fissidens species covering all sections and subgenera, three types of costae are recognized. One type is characteristic of sect. Amblyothallia and of F. asplenioides, F. fasciculatus and F. plumosus (the fasciculatus group); the second of subg. Serridium, subg. Fissidens sect. Crispidium andF. Grandifrons (subg. Pachyfissidens) and the third type of subg. Fissidens sect. Fissidens, sect. Aloma, sect. Crenularia, sect. Semilimbidium, sect. Pycnothallia, and sect. Areofissidens, subg. Octodiceras, and subg. Sarawakia.
A new moss genus and species, Gradsteinia andicola, is described from the northern Andes of Colombia. It is an aquatic moss known sterile and characterized by 1) oblong or oblong-ovate, concave, cucullate and recurved-apiculate leaves with a very strong and variable costa that is basically single but commonly repeatedly branched and spurred from the base, giving the leaves a polycostate appearance; 2) thick-walled, porose and irregularly uni- to multistratose lamina cells; 3) bicellular axillary hairs; 4) the presence of incomplete limbidia; 5) the absence of paraphyllia, pseudoparaphyllia, central strand and alar cells. Until the sporophyte of Gradsteinia becomes known, this very distinct genus is tentatively placed in the family Donrichardsiaceae, based primarily upon the presence of variously multistratose leaf laminae and leaf areolation.