Vernonia chochisensis (Compositae: Vernonieae), a new species from the Serranía de Chochís, Mun. Roboré, Departamento de Santa Cruz, eastern Bolivia

Résumé fourni par la source

Summary Vernonia chochisensis (Compositae: Vernonieae), a new species from the Serranía de Chochís, Mun. Roboré, Departamento de Santa Cruz, eastern Bolivia, is described and illustrated. It is a bonsaied (or dwarfed) tree-like species, exhibiting several characters that separately, and in combination, place it in an interesting position in Vernonia s.l. The few, first-formed and flowering, subsessile capitula appear to be surrounded by rosettiform leaves, the inflorescence scarcely forming a recognisable simple scorpioid cyme. Later, as more capitula are produced, each is subtended by a leaf-like bract (originally forming the part of the apical rosette), with the stem scars evidence of the scorpioid arrangement. Continued, indeterminate, growth of the axis results in the old inflorescence being overtopped, as is typical in the family, and frequently from vegetative branching beneath the apical rosettiform leaves. Vernonia ‘Type D’ pollen (sensu Robinson) found in V. chochisensis is also present in a few species referred to Vernonia sect. Lepidaploa (Cass.) DC., in the subtribe Lepidaploinae S.C.Keeley & H.Rob. However, in Vernonia chochisensis the style lacks a basal node, the achenes are ribless and the biseriate pappus setae are proximally flattened with lacerate margins, and distally coarsely capillary and barbellate, unlike any currently known species in V. sect. Lepidaploa .

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