NOTES ON SOME SPECIES OF COLURA (LEJEUNEACEAE, JUNGERMANNIOPSIDA), WITH DESCRIPTION OF COLURA CATARACTARUM FROM MADAGASCAR

Examination of about one hundred unidentified Colura specimens resulted in new distri-butional data of eleven uncommon species, C. australiensis , C. bicornis , C. calyptrifolia , C. crispiloba , C. cristata , C. heimii , C. humbertii , C. imperfecta , C. obesa , C. rhynchophora, C. saroltae and a new species of sect. Colura from Madagascar, C. cataractarum.


INTRODUCTION
During the past decades I accumulated nearly one hundred unidentified specimens of the liverwort genus Colura (Dumort.) Dumort. (Lejeuneaceae) from different parts of the world, mostly from East Africa, Australia and the Fiji Islands, collected by myself, my wife and my colleagues. The identification of the material resulted in a large number of range extensions and recognition of a new species of section Colura, C. cataractarum Pócs, from Madagascar. In this paper new localities and range extensions of eleven uncommon species as well as the description of the new species are presented.

RANGE EXTENSIONS
In the present enumeration the first two digits of locality numbers refer to the year of collection, while the letters mark the different species within the same locality. The novelty of the records was mostly established using Ah-Peng and Bardat (2005) and Ah-Peng et al. (2010a, b) for Réunion, Grolle (1995) and Marline et al. (2012) for Madagascar and the Mascarenes, McCarthy (2003) for Australia, Söderström et al. (2011) for Fiji and Wigginton (2018) for continental Africa.

DISCUSSION
Since the publication of World checklist of hornworts and liverworts (Söderström et al. 2016) four new species of Colura have been described, hence the total number of species in this genus, according to our present knowledge, is 86. The number may change in the future with synonymization and description of further species. A notable feature of the genus is that the greater part of the species is endemic, while several species are worldwide distributed or at least pantropical. This can be the result partly of their quick and steady evolvement since the Cretaceous (Feldberg et al. 2014, Wilson et al. 2007, partly of the ability of many species for vegetative reproduction by mass production of disciform gemmae. These develop in endo-or exogenous ways (Pócs 2012), usually at the upper end of the sacciform lobule and sometimes on the perianth. The gemmae might be more successful in long range dispersal than the large, protonematic spores attaining sometimes 100 µm in length in many species (Weiss 2001). The fully developed gemmae of different Colura species have the same diameter (80-100 µm), but being lighter and having much larger specific surface due to their shape (Zanten and Pócs 1981) they have a good chance to float in the air. Their survival ability is not yet experimentally checked. It is notable that the autoicous, worldwide distributed Colura calyptrifolia has relatively small, unicellular spores (Jovet-Ast 1954).
Examples of endemic species are the Melanesian endemics (Fig. 23) C. australiensis, C. crispiloba and C. vitiensis Eggers et Pócs (the latter reaching westwards to the Solomon Islands; Pócs 2013), and C. queenslandica B. Thiers, a narrow endemic of Queensland (Thiers 1987). Colura heimii and C. humbertii, hitherto considered endemic to Madagascar and the Mascarene Islands, have become known also from the Nguru Mts of Tanzania (Fig. 24). These two species are joining the group of more than 50 "Lemurian" elements (Pócs 1975, 1982, PÓCS, T. 2000, Tixier 1978) occurring in Madagascar and the crystalline Eastern Arc mountain range of mainland Africa, extending from southern Kenya to southern Tanzania.
The new species, C. cataractarum, represents a small group within section Colura characterised by the hood-like, relatively wide conical sac, approaching morphologi cally the sect. Oidocorys. In fact, these two sections, characterised by their valves with 2 triangular basal-median cells (Grol le and Zhu 2002), represent related, sister lineages within the subgenus Colura, separated from the sect. Harmophyllum (Heinrichs et al. 2012). Colura cataractarum seems to be a narrow endemic of Madagascar, similarly in distribution to C. bicornis (Fig. 22).
The Andringitra Mas sif, where the new species was found, is particularly rich in endemics compared with other Mada gas car localities, and several new bryophyte taxa have recently been described from this area. Examples of rare taxa of this area include Amazoopsis diplopoda (Pócs) J. J.  (Fig. 14), the latter growing on tree-fern stems and decaying logs in mossy montane rainforest (Pócs 9473/AF,EGR,TAN). This species is new to Madagascar, hitherto being known only from Zimbabwe (Sim 1926) and Réunion . A good illustration of the species is available in the Icones of Stephani (1985Stephani ( : 1833.
As the new records of the Colura species have demonstrated, the ranges of the species of this large genus are still very imperfectly known. To obtain a more precise picture, many more specimens have to be studied by morphotaxonomic and molecular methods.