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Shuaria (Gesneriaceae), an arborescent new genus from the Cordillera del Cóndor and Amazonian Ecuador

Abstract:

A new neotropical genus, Shuaria, with a single species, S. ecuadorica, is described from the Cordillera del Cndor and Amazonian regions of southeastern Ecuador and is placed in the family Gesneriaceae, tribe Beslerieae. The placement of Shuaria in the tribe Beslerieae is strongly supported by molecular sequence data generated from analyses of nuclear ribosomal DNA internal transcribed spacer region (ITS), and the chloroplast DNA trnL intron, trnL-trnF intergenic spacer region. Sequence data were generated for 33 species representing most of the generic diversity from the tribes Beslerieae and Napeantheae. Shuaria is characterized by the following unique combination of relatively uncommon characters in the Gesneriaceae: arborescent habit; opposite leaf arrangement sometimes interrupted by alternate leaves; lepidote trichomes on vegetative and floral structures; small white flowers with a dorsal gibbosity at the base of the corolla tube; and a bivalved septicidally dehiscent capsule. The suite of uncommon characters initially made Shuaria difficult to place in the Gesneriaceae and within a known tribe. Shuaria is restricted to the Ecuadorian provinces of Pastaza, Morona-Santiago, and Zamora-Chinchipe in lowland Amazonian tropical wet forest and in lower montane cloud forest on the western slopes of the Cordillera del Cndor. A key and a table are presented for differentiating Shuaria from other related genera. © 2010 by the American Society of Plant Taxonomists.