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Recent molecular and morphological studies suggest that neither Acleisanthes nor Selinocarpus (Nyctaginaceae) are monophyletic as currently circumscribed. Further, these data provide no basis for continued recognition of the monotypic genus Ammocodon as separate from these other two genera. Therefore, all 8 Selinocarpus species and the monospecific Ammocodon are transferred to Acleisanthes; 3 additional Selinocarpus species are reduced to synonymy. The genus Acleisanthes is now composed of 16 species, distributed primarily in the Chihuahuan Desert of North America. Diagnostic features of Acleisanthes include an herbaceous or woody perennial habit in arid environments, and the presence of both cleistogamous and chasmogamous flowers often simultaneously on an individual plant. Further, flowers are usually axillary and subtended by 1 to 4 subulate bracts, with chasmogamous flowers frequently white or yellow and funnelform to salverform.

Nyctaginaceae are a small family of mainly New World tropical and subtropical trees, shrubs, and herbs. To date phylogenetic relationships within the family have not been examined. This study provides the first phylogenetic hypothesis of relationships within Nyctaginaceae tribe Nyctagineae based on sequence data from both nuclear (ITS) and chloroplast (accD 5‘coding region and intergenic region between the rbcL and accD genes). Morphological characters are also discussed as they relate to the phylogeny inferred using molecular data. Results suggest that neither Acleisanthes nor Selinocarpus is monophyletic but that together they comprise a monophyletic lineage. The genus Mirabilis is strongly supported as monophyletic, but the monophyly of two of its sections is suspect. Morphology generally agrees with the molecular data and in some instances reinforces clades weakly supported by nuclear and chloroplast data. Further sampling will help clarify relationships of these genera within Nyctaginaceae. ...

Investigations of the hormonal control of avian territorial aggression have focused on temperate zone species where typically only males sing and defend territories in the breeding season, and have implicated testosterone in the control of these behaviors. However, most avian species are tropical and in many such species both sexes sing and defend year-round territories. We have examined the mechanisms underlying territoriality in the White-browed Sparrow Weaver Plocepasser mahali, in Zambia, and the Bay Wren Thryothorus nigricapillus, in Panama. In both species, we found low circulating levels of steroid hormones and no evidence for the regulation of territorial aggression by testosterone even in the breeding season. However, there were preliminary indications of a role for luteinizing hormone in maintaining territorial aggression. Thus, in contrast to temperate zone species, territorial aggression in these two tropical species is either independent of control by steroid hormones or is mediated by a non-gonadal hormone. These results, and the few data from other tropical species, suggest that the general assumption that androgens maintain territorial aggression may apply only to temperate species.