A new species of Heteranthera (Pontederiaceae), H. yucatana, is described, discussed, and iconographically documented based on material from Yucatan state, Mexico. The species is known from a few small ponds along a narrow strip of dry forests and shrublands over limestone outcrops and derived soils along the northwestern edge of the Yucatan Peninsula. The new species is related and has been hitherto confused with H. seubertiana from eastern Brazil but is easily distinguishable by its substantially smaller habit and flowers. Furthermore, the perianth lobes are lilac with a white-greenish basal blotch with yellowish towards the apex (as opposed to yellow lobes with proximal brownish spots). Also, the two lateral filaments are conspicuously inflated obliquely, as in Heteranthera mexicana, from which it differs by its much smaller vegetative size and some floral characters. The conservation status of the new species is assessed as Endangered according to the IUCN criteria. The genus Heteranthera consists of three species in the Yucatan Peninsula: H. dubia, H. limosa, and H. yucatana. Distributional maps for all Heteranthera from the area covered are presented. Finally, we offer a key to Heteranthera of the area.
In Venezuela, Roystonea oleracea commonly forms communities in flooded and swampy areas on fertile soils mainly in the northern portion of the Orinoco river basin. The density of R. oleracea varies across its range from dominating the canopy to being rare. Communities dominated by R. oleracea are distributed across the country from the east (Sucre and Monagas States) to the south-west (Barinas State). In the western-central region the Roystonea community is mainly present along the Tocuyo, Yaracuy and Aroa river basins. In all most cases, R. oleracea is found with other palms such as Bactris major var. major, trees including Tabebuia rosea, Ficus spp., Spondias mombin, Triplaris americana, Hura crepitans or herbs (e.g. Heliconia spp.). In the western part of its range, it is found with another set of species, including Anacardium excelsum, Hirtella spp. and the large palm Attalea butyracea; in the eastern parts of its range it is found with the climbing palm Desmoncus horridus subsp. horridus and the tree Virola surinamensis and the mangroves Rhizophora racemosa and Avicennia germinans in estuarine environments of the Orinoco Delta. Human intervention in these communities has been intense due to agriculture involving clearing for sugar cane and orange plantations, hunting and extraction of young parrots (Psittacidae) from nests for the pet trade. These activities have endangered the survival and conservation of R. oleracea forests, which have been greatly reduced across the country.
The new species Bonamia jiviorum J. R.Reslimen. Se describe e ilustra Bonamia jiviomm J. R. Grande ( Convolvuloideae, Cresseae) del norocciirregulannente estriada. con alas sobre las aristas
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