Two new Lejeuneaceae records for the Colombian liverwort flora

Two epiphyllous Lejeuneaceae, Cololejeunea surinamensis and Drepanolejeunea polyrhiza, previously known from Amazonian Brazil, are recorded for the first time in Colombia. They were found as epiphylls on understory shrubs in the middle Caquetá area in Colombian Amazonia. Cololejeunea surinamensis was found in the Tierra Firme forests and D. polyrhiza was found in the floodplains of the Caquetá River.Dos especies de Lejeuneaceae epífilas, Cololejeunea surinamensis y Drepanolejeunea polyrhiza, previamente conocidas de los bosques amazónicos de Brasil son reportadas por primera vez para Colombia. Las especies fueron encontradas como epífilas sobre hojas de arbustos del sotobosque en el área del medio Caquetá en la amazonía Colombiana. Cololejeunea surinamensis fue encontrada en los bosques de tierra firme, mientras que D. polyrhiza fue encontrada en los planos inundables del Río Caquetá

Regular and chaotic motion in elliptical galaxies

Here I review recent work, by other authors and by myself, on some particular topics related to the regular and chaotic motion in elliptical galaxies. I show that it is quite possible to build highly stable triaxial stellar systems that include large fractions of chaotic orbits and that partially and fully chaotic orbits fill different regions of space, so that it is important not to group them together under the single denomination of chaotic orbits. Partially chaotic orbits should not be confused with weakly fully chaotic orbits either, and their spatial distributions are also different. Slow figure rotation (i.e., rotation in systems with zero angular momentum) seems to be always present in highly flattened models that result from cold collapses, with the rotational velocity diminishing or becoming negligibly small for less flattened models. Finally, I comment on the usefulness and limitation of the classification of regular orbits via frequency analysis.Comment: 12 pages, 2 figures (both are mosaics of 6 and 4 individual figures, respectively, in eps format). It is an invited talk delivered at the workshop "Chaos in Astronomy 2007", in memory of N. Voglis, held in Athens (Greece), 17 - 20 September 2008, and accepted for publication in the Proccedings of that worksho

Non-existence of an invariant measure for a homogeneous ellipsoid rolling on the plane

It is known that the reduced equations for an axially symmetric homogeneous ellipsoid that rolls without slipping on the plane possess a smooth invariant measure. We show that such an invariant measure does not exist in the case when all of the semi-axes of the ellipsoid have different length.Comment: v2: Minor changes after journal review. This text uses the theory developed in arXiv:1304.1788 for the specific example of a homogeneous ellipsoid rolling on the plan