Systematics value and evolution of morphological characters in Stenocephalum Sch.Bip.: insight into the relationships in the Lepidaploinae subtribe (Vernonieae, Asteraceae).
ANGULO, M. B.; CHALUP, L.; DEMATTEIS, M.
TURKISH JOURNAL OF BOTANY
TUBITAK SCIENTIFIC & TECHNICAL RESEARCH COUNCIL TURKEY
Micromorphologicaland palynological characters of all StenocephalumSch.Bip. species (Vernonieae, Asteraceae) were analyzed to evaluate their reliabilityas taxonomic markers at generic level and discussed in relation to other generaof the Lepidaploinae subtribe. Characters such as pubescence ofcorollas and cypselae showed glandularand non-glandular trichomes allowing to differentiating among related species.Apical appendages without glandular trichomes, caudate anthers, and carpopodiumstructure are common characteristics among Stenocephalumspecies. With the exceptions of S.megapotamicum and S. tragiaefolium, amostall species of the genus showed style base without basal node for the firsttime. Crystals on the fruits wall were also observed for the first time in almostall the Stenocephalum species, withthe exception of S. hystrix. However,the crystals would not constitute diagnostic features, since it varies widelyamong species. All thespecies showed pollen type C and the genus is considered stenopalynous.However, highly significant differences in palynological features among thespecies of the genus were observed. The different combinations of the micromorphologicaland palynological features of Stenocephalumhere analyzed are valuable within genera to differentiate related species fromone another. The value of all these characters could be increased if they arecombined with other morphological or traditional data.