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Apomictic plants mostly occur at higher latitudes and higher elevations, where they tend to occupy deglaciated areas. By analysing samples of the alpine floras of different latitudinal zones of the Americas (Argentina, Bolivia, Ecuador, USA), we investigated whether the proportion of gametophytic apomixis is comparable between the temperate alpine zones of the Northern Hemisphere and the Southern Hemisphere and whether the proportion of apomictic species increases from the alpine tropics towards the temperate alpine zone. The reproductive systems of 196 species and 275 individuals were determined by a flow-cytometric seed screening of 999 seeds. Phylogenetic logistic regression was used to evaluate differences in the proportion of apomictic species in samples of regional alpine floras. The apomictic embryo:endosperm ratio was determined for 33 species (two pseudogamous species and 31 species with autonomous apomixis) belonging to 28 genera of 13 families. The probability of a species being apomictic did not significantly differ between the regions. The highest probability of a species being apomictic was estimated for the northern temperate zone (29.6%), followed by the tropical zone (12.5%), and the southern temperate zone (11.9%). Our results show that asexual plant reproduction by apomixis is not restricted to the alpine zone of the Northern Hemisphere and its representation in alpine floras of the Southern Hemisphere, including the alpine tropics, has been substantially underestimated. [ABSTRACT FROM AUTHOR]

Two new species of Rubus (Rosaceae) from the western Andes of northern Ecuador are described. Rubus longistipularis D.A. Espinel-Ortiz & Romol. is a scandent or climbing shrub found in the mountain forests of Chocó Andino from northern Ecuador. Rubus maquipucunensis D.A. Espinel-Ortiz & Romol. is a vine or climbing shrub found in the rainforests of Chocó Andino from Pichincha and Santo Domingo de los Tsáchilas. The species mentioned here are morphologically differentiated from all the Rubus species from Ecuador with a detailed botanical description, illustrations and photographs. We also report, for the first time, possible hybridisation between R. longistipularis and R. boliviensis Focke, as the samples reviewed showed mixed characteristics from both species. [ABSTRACT FROM AUTHOR]

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The Andean uplift is recognized as one of the most important events shaping the Neotropical biota. Previous phylogenetic reconstructions of Nasa , a mostly tropical Andean genus, have been unable to address its historical biogeography or ancestral character estimations in detail due to insufficient sampling and phylogenetic resolution. The main goal of the present study is to provide an expanded and highly resolved phylogenetic reconstruction of the genus to address these questions. We were able to sequence 87 of the 125 taxa (species and subspecies) of Nasa , for the plastid markers trnL–trnF , matK , trnS–trnG and rps16. Our results show that Nasa falls into four well-supported clades, clade I is sister to the rest of the genus and is composed of Central Andean species. The remaining three clades are more widely distributed, found also in the Amotape-Huancabamba Zone (AHZ) and the northern Andes. Our morphological analyses were able to identify plausible phylogenetic affinities of most Nasa spp. for which molecular data are unavailable, with three of the morphological clusters composed mostly by species of three well-supported clades (Clades II, III and IV). Historical biogeography indicates that Nasa has a history spanning 50 Myr, its early events predating most of the Andean uplift. Nasa appears to have originally occupied mid-elevation, seasonally dry habitats. By the mid-Miocene (c. 15 Mya) expansion into new forest edge and undergrowth habitats took place. This coincides with renewed uplift that increased the complexity of the abiotic conditions in the Andes. The AHZ is retrieved as the most important centre of diversification since the closure of the West Andean Portal and appears to be a cradle of clades of Nasa. Conversely, the central Andes, the most likely area of origin of the genus, house mostly ancient, species-poor clades. [ABSTRACT FROM AUTHOR]