Two New Species of Heterocoma (Asteraceae: Vernonieae) and a Broadened Concept of the Genus
Abstract—
A new concept of the genus Heterocoma is presented based on morphological and anatomical evidence. The genus is characterized by the combination of foliose subinvolucral bracts, fimbrillate or paleaceous receptacles, glabrous cypselae, and a caducous biseriate pappus (at least the inner series). A putative synapomorphy of the genus is the presence of phytomelanin in the cypselae walls. The monotypic genera Bishopalea, Sipolisia, and Xerxes are synonymized under Heterocoma with the following new combinations: Heterocoma ekmaniana , Heterocoma erecta , and Heterocoma lanuginosa . Two new species, Heterocoma gracilis and Heterocoma robinsoniana , are described and illustrated. The genus is endemic to the campos rupestres of the Brazilian Central Plateau. A key to the six species recognized in Heterocoma is provided.
A new concept of the genus Heterocoma is presented based on morphological and anatomical evidence. The genus is characterized by the combination of foliose subinvolucral bracts, fimbrillate or paleaceous receptacles, glabrous cypselae, and a caducous biseriate pappus (at least the inner series). A putative synapomorphy of the genus is the presence of phytomelanin in the cypselae walls. The monotypic genera Bishopalea, Sipolisia, and Xerxes are synonymized under Heterocoma with the following new combinations: Heterocoma ekmaniana , Heterocoma erecta , and Heterocoma lanuginosa . Two new species, Heterocoma gracilis and Heterocoma robinsoniana , are described and illustrated. The genus is endemic to the campos rupestres of the Brazilian Central Plateau. A key to the six species recognized in Heterocoma is provided.
Keywords: Brazil; Compositae; Sipolisiinae; phytomelanin; taxonomy
Document Type: Research Article
Publication date: 01 March 2013
- Systematic Botany is the scientific journal of the American Society of Plant Taxonomists and publishes four issues per year.
2011 Impact Factor: 1.517
2011 ISI Journal Citation Reports® Rankings: 87/190 - Plant Sciences
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