Una nueva especie costarricense del género Amyris P. Browne (Rutaceae)

Una nueva especie de Amyris P. Browne (Rutaceae), con hojas muy grandes, opuestas y pinnadas, se describe de la región del Pacífico central y sur de Costa Rica.A new species of Amyris P. Browne (Rutaceae) with large opposite pinnate leaves is described from the central and southern Pacific region of Costa Rica.

La sabana arbolada "El Escobio", Liberia, Guanacaste, Costa Rica

La sabana arbolada “El Escobio” (Guanacaste, Costa Rica), es una comunidad natural donde no hay pasto jaragua (Hyparrhenia rufa) y la alteración antrópica es mínima. Presenta suelos arenosos, donde la materia orgánica es lavada con facilidad; su vegetación es dominada por gramíneas y ciperáceas (estrato herbáceo) y un estrato arbóreo disperso, xeromórfico y achaparrado, en donde predomina el encino (Quercus oleoides), el nance (Byrsonima crassifolia) y el raspaguacal (Curatella americana). Debido a sus características tan inhóspitas, este sitio constituye un mal refugio para la mayoría de las especies de animales.Los bosques de galería, tanto del río Liberia como el de la Quebrada “I Griega”, tienen suelos con cierto grado de fertilidad y presentan una gran diversidad de vegetación (148 especies, 64 familias). Así pues, se sugiere que estos bosques, representan un buen refugio y produce un gran número de recursos usados por animales.An ecological study of a tree savanna was conducted at “El Escobio”, Liberia, Guanacaste, Costa Rica. The site shows a seasonal climate; with well defined dry and wet seasons. Soils are poor on nutrients, favouring a dominant coverage of herbaceous plants (Cyperaceae and Graminae) more or less xeromorphic, and the growth of some scattered tree species.A great number of rare and economically important species were found at the riparian forest. This forest plays a significative role in keeping a diverse fauna, due to the variety of fruits and flowers available throughout the year

A new species of Ternstroemia (Pentaphylacaceae) from La Amistad Binational Park and World Heritage Property, Costa Rica and Panama.

Ternstroemia amistadensis Q. Jiménez & D. Santam., a new tree species from La Amistad International Park in Costa Rica and Panama, is described and illustrated. Ternstroemia amistadensis is assessed as Near Threatened, It may be may be distinguished from other species in the genus based on its obovate, coriaceous and very shiny leaf laminae with obtuse-rounded apices and bearing many small black punctations below

Two New Species ofFreziera(Pentaphylacaceae) from Costa Rica

© President and Fellows of Harvard College, 2014. Two new species of Freziera endemic to Costa Rica, F. tarariae from the Cordillera de Talamanca and F. bradleyi from the Cordillera Central, are described and illustrated. Their distribution, phenology, habitat, and relationship to allied species are discussed

Separation of crude plant extracts with high speed CCC for primary screening in drug discovery

High speed countercurrent chromatography (HSCCC) was used in a pre-fractionation pilot study to improve the quality of crude plant samples for primary screening in drug discovery efforts. The methanol extracts of sixty-four plant samples were (i) defatted, (ii) treated with poly-N-vinylpyrrolidone (PVP) for polyphenolic removal, and (iii) fractionated with a multilayer coil planet centrifuge. The ternary solvent system CH2Cl2:MeOH:H2O (5:6:4, v/v/v) was used based upon elution of known plant natural product standards with ranging polarities. Elution was carried out until a partition coefficient (K) of 1, followed by column contents extrusion to exploit stationary phase separation and to increase the polarity range of compounds, fractionated. Fractionation was found to be consistent for all separated extracts with respect to sample recovery, stationary phase fraction (Sf), and weight distribution by fraction number. Biological evaluation was conducted in 20 mechanism-based, in-vitro assays with an evaluation of biodata trends. Bioassay interfering agents such as polyphenolics and fatty acids were chromatographically localized and rapidly identified.UCR::Vicerrectoría de Docencia::Ciencias Básicas::Facultad de Ciencias::Escuela de Químic

Two New Species of Freziera

© President and Fellows of Harvard College, 2014. Two new species of Freziera endemic to Costa Rica, F. tarariae from the Cordillera de Talamanca and F. bradleyi from the Cordillera Central, are described and illustrated. Their distribution, phenology, habitat, and relationship to allied species are discussed