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Micromorphological and palynological characters of all Stenocephalum Sch.Bip. species (Vernonieae, Asteraceae) were analyzed to evaluate their reliability as taxonomic markers at generic level and discussed in relation to other genera of the subtribe Lepidaploinae. Characters such as pubescence of corollas and cypselae showed glandular and nonglandular trichomes allowing differentiation among related species. Apical appendages without glandular trichomes, caudate anthers, and carpopodium structure are common characteristics among Stenocephalum species. With the exceptions of S. megapotamicum and S. tragiaefolium, almost all species of the genus showed style bases without basal nodes for the first time. Crystals on the fruits wall were also observed for the first time in almost all the Stenocephalum species, with the exception of S. hystrix. However, the crystals would not constitute diagnostic features, since they vary widely among species. All the species showed type C pollen and the genus is considered stenopalynous. However, highly significant differences in palynological features among the species of the genus were observed. The different combinations of the micromorphological and palynological features of Stenocephalum here analyzed are valuable within genera to differentiate related species from one another. The value of all these characters could be increased if they are combined with other morphological or traditional data. [ABSTRACT FROM AUTHOR]

The pollen grains of 111 species of Lessingianthus were analysed. Almost all the species belong to the type “B” pollen, characteristic of the genus. These grains are oblate-spheroidal, spheroidal to prolate-spheroidal (P/E 0.93-1.04), echinolophate, 3-colporate, with lacunae in a regular pattern, without polar lacunae. However, some species show variations of this basic type. The type “B-1”, “B-2” and “B-3” grains are respectively 3-porate lacking equatorial lacunae, 3-porate with equatorial lacunae and 3-colporate, psilolophate. Also, one species showed type “D” pollen, a palynomorph present in other genera of the tribe but not reported until now for Lessingianthus. The analysis confirms that the species of the genus constitute well-defined groups based on the pollen characteristics. The results ascertain that pollen morphology is a significant feature in the identification and delimitation of species and genera of Vernonieae. [ABSTRACT FROM AUTHOR]

Eupatorium rufescens Lund ex DC. and Vernonia oligactoides Less. (Asteraceae) are recorded for the first time for Argentina. Both species are described and a key to separate them from related taxa, along with some ecological information on the entities is also presented. [ABSTRACT FROM AUTHOR]

A new species of the genus Chresta Vell. ex DC. (Vernonieae, Asteraceae) from the Brazilian state of Bahia is described and illustrated. The new species resembles Chresta pinnatifida (Philipson) H.Rob. but differs in having solitary glomerules, leaf bases clasping the stem and 35–40 capitula per glomerule. It can be distinguished from Chresta harleyii and Chresta martii, the other two species of the genus with pinnately lobed leaves, by the type of pubescence, leaf blade bases and florets number. In addition, a key to distinguish all the species of the genus is presented. © 2008 The Linnean Society of London, Botanical Journal of the Linnean Society, 2008, 157, 587–590. [ABSTRACT FROM AUTHOR]

Mitotic or meiotic chromosome numbers for 42 accessions belonging to 39 species of different genera of Asteraceae were determined. First chromosome counts are reported for one genus ( Gymnocoronis), 14 species, and one variety. These are as follows: Solidago chilensis var. megapotamica (2 n = 2 x = 18), Chromolaena barbacensis (2 n = 3 x = 30), Chromolaena christieana (2 n = 3 x = 30), Chromolaena hirsuta (2 n = 4 x = 40), Chromolaena verbenacea ( n = 20 II, 2 n = 4 x = 40), Disynaphia multicrenulata (2 n = 2 x = 20), Gymnocoronis spilanthoides var. subcordata (2 n = 2 x = 20), Mikania thapsoides (2 n = 4 x = 68), Stevia commixta (2 n = 2 x = 22), Porophyllum brevifolium (2 n = 4 x = 44), Viguiera rojasii (2 n = 2 x = 34), Pterocaulon angustifolium (2 n = 2 x = 20), Gochnatia haumaniana (2 n = 4 x = 44), Senecio ostenii (2 n = 4 x = 40), Senecio pinnatus (2 n = 8 x = 80), and Lepidaploa amambaia (2 n = 2 x = 28). Chromosome numbers differing from those reported previously in the literature were found in Campuloclinium macrocephalum (2 n = 2 x = 20), Melanthera latifolia (2 n = 4 x = 60), Chrysolaena flexuosa (2 n = 2 x = 20), and Cyrtocymura cincta (2 n = 4 x = 40). The relevance of the results is discussed in relation to the available data for each of the analysed taxa. © 2007 The Linnean Society of London, Botanical Journal of the Linnean Society, 2007, 153, 221–230. [ABSTRACT FROM AUTHOR]