Studies on Colombian cryptogams XVII . On a new antipodal element in the Neotropical Paramos-Dendrocryphaea latifolia sp . nov . ( Musci )

Dendrocryphaea latifolia sp.nov. from the Páramo de Chisacá, Colombia is described and illustrated. It is allied to D. cuspidata from austral South America but differs from that species in the broader leaves, globose capsules and the basally smooth exostome teeth. A key to the four species of Dendrocryphaea and a conspectus ofthe genus are provided. D. ramosissima is reduced to synonymy under D. lechleri. Dendrocryphaea is a rheophytic genus with antipodal distribution. Its discovery in the high Andes of Colombia extends to 34 the number of genera of bryophytes with similar antipodal affinities known from the páramos of the northern sector of the Andean cordillera, The nature and origin of these distribution patterns is discussed. In the case of Dendrocryphaea wind and birds may have played a role in the transport of spores and the establishment of its present distribution.

Protonemal notes: protonemata were obtained from spores dessicated for periods of 2, 5 and 11 months after collecting and subsequently exposed to wet or dry freezing at -30°C for 1-4 days. Germination rates were over 50% after on the emergent plants only, as is typical of rheophytic bryophytes (Gradstein & Vital 1975 (Cleef 1981), of which Dendrocryphaea latifolia is the local character species. In the paramos of Colombia this community is not uncommon on rocks in streams, where it is usually made up of monotypic strands of Platyhypnidium (Cleef 1981). We assume, however, that a careful searching in the habitats where the community occurs might reveal additional localities for D. latifolia.

TAXONOMIC NOTES
The new species is allied to Dendrocryphaea cuspidata (Sull.) Broth, from Dendrocryphaea latifolia can be added to a small, but increasingly better known, group of taxa with similar distributions (Cleef 1978 (Engel & Schuster 1974), Telaranea subg. Neolepidozia and Temnoma (Schuster 1979 (Engel 1980) and Triandrophyllum subtrifidum (Grolle 1969 (aquatic, terrestrial, corticolous). the geographical ranges of these species reveal also great differences in terms of continuity of distribution.
Some occur all along the Andean Cordillera with disruptions of, at most, a few hundred kilometers. Others include disjunctions of over 1,000 kilometers. The possibility that these disjunctions are, at least in part, artifacts caused by insufficient collecting in intermediate areas should of course not be ruled out.
Obviously, no one explanation will clarify the question of how this element came to inhabit the paramos. Speculation concerning the origin needs to address both time and mode of arrival. Given that the paramo life zone has existed for, at most, 1.8-2 millions of years (Van der Hammen 1974), it seems probable that these bryophytes evolved elsewhere, migrating to the paramos concurrent with or following the development of the paramo environment. The relatively recent appearance of the paramos does not exclude the possibility of an earlier arrival to the area by at least some of these taxa. Several species, e.g. Rhizogonium mnioides, Lepyrodon tomentosus, Jamesoniella rubricaulis, Triandrophyllum subtrifidum, also occur in the high Andean forests, suggesting that their appearance in northern South America may not have depended entirely upon a paramo life zone. As botanists with field experience will attest, the conditions of the paramos grade, at times imperceptibly, slope down into the upper reaches of the Andean forests. The tolerances of some of these species quite clearly allow them to exist in both types of habitats.
As to the mode of arrival, few concrete data are at hand. The experiments on spore viability and germination bij Van Zanten (1978) suggest that for certain austral latitude moss-species strong, directional winds may have carried viable spores from one area to another (e.g. from New Zealand to southern Chile), and, if so, then no more complicated vector need to be sought. According to Dr. Van Zanten (oral comm.) the data on spore germination for Dendrocryphaea latifolia indicate a moderate drought resistance of its spores and a capacity for air travel over longer distances. It is not certain, however, that winds of the required force and duration have ever persisted between, say, Patagonia and Colombia or that spores could withstand airborne passage over the arid Atacama barrier.
Jovet-Ast (1980) concluded, in reference to the Gondwanic Colura sect. Oidocorys (which includes C. patagonica, fig. 8), that wind and birds could account for dispersal over short distances, but that disjunctions across oceans would be explained better by continental drift. In some of these disjunct taxa, however, e.g. Eopleurozia paradoxa ( fig. 9), neither sporophytes nor any other obvious means of propagation have been found. Thus, their geographical ranges would seem to represent very ancient migrations and relict occurrences.
When and by what route these migrations occurred is difficult to say. Via the eastern slopes of the Andes? The remarkable neotropical occurrence of Eopleurozia paradoxa in such disparate localities as the northern Andes and the tepui district of eastern Venezuela invites reflection on this possibility.