A new species of Cinnamomum (Lauraceae) from the Bladen Nature Reserve, southern Belize.

A new species in the Lauraceae, Cinnamomum bladenense S.W. Brewer & G.L. Stott, is described from the Bladen Nature Reserve in southern Belize. The new species is similar to Cinnamomum brenesii (Standl.) Kosterm., from which it differs by its much smaller, narrowly-campanulate flowers, its inner tepals glabrous abaxially, its shorter petioles, its minutely sericeous younger twigs, and its abaxial leaf surfaces not glaucous and with prominent secondary venation. A description, preliminary conservation assessment, and photographs of the species as well as a key to and notes on the Cinnamomum of Belize are provided.

Iron controls over di-nitrogen fixation in karst tropical forest.

Limestone tropical forests represent a meaningful fraction of the land area in Central America (25%) and Southeast Asia (40%). These ecosystems are marked by high biological diversity, CO2 uptake capacity, and high pH soils, the latter making them fundamentally different from the majority of lowland tropical forest areas in the Amazon and Congo basins. Here, we examine the role of bedrock geology in determining biological nitrogen fixation (BNF) rates in volcanic (low pH) vs. limestone (high pH) tropical forests located in the Maya Mountains of Belize. We experimentally test how BNF in the leaf-litter responds to nitrogen, phosphorus, molybdenum, and iron additions across different parent materials. We find evidence for iron limitation of BNF rates in limestone forests during the wet but not dry season (response ratio 3.2 ± 0.2; P = 0.03). In contrast, BNF in low pH volcanic forest soil was stimulated by the trace-metal molybdenum during the dry season. The parent-material induced patterns of limitation track changes in siderophore activity and iron bioavailability among parent materials. These findings point to a new role for iron in regulating BNF in karst tropical soils, consistent with observations for other high pH systems such as the open ocean and calcareous agricultural ecosystems.

Spathelia belizensis, a new species and first record for the genus in Central America (tribe Spathelieae, Rutaceae).

Spathelia L. as currently circumscribed is endemic to the western portion of the West Indies, and contains nine species, one endemic to the Bahamas, three endemic to Jamaica and five endemic to Cuba. The discovery of a new species in Belize brings the total number of species in Spathelia to ten and expands its known distribution beyond the West Indies. Spathelia belizensissp. nov. is herein described, illustrated and contrasted to its most morphologically similar congener. A key to the species of Spathelia is provided.

ResumenEl género Spathelia es en la actualidad circunscrito como endémico de la porción occidental de las Antillas con un total de nueve especies, una endémica de las Bahamas, tres endémicas de Jamaica y cinco endémicas de Cuba. El descubrimiento de una nueva especie en Belice amplía el número total de especies a diez y expande la distribución del género más allá de las Antillas. En este artículo Spathelia belizensis es descrita e ilustrada y se compara con el congénere morfológicamente más similar. También, se proporciona una clave para las especies de Spathelia.