Taxonomic Identity of the ‘talas’: Morphological analysis of Celtis tala and Celtis pallida (Celtidaceae).

Abstract

Taxonomic Identity of the ‘talas’: Morphological analysis of Celtis tala and Celtis pallida (Celtidaceae).
The genus Celtis (Celtidaceae) comprises around 70 temperate to tropical woody taxa . In Argentina there appear four species, all of them belonging in the subgenus Mertensia Planch., whose inter and intraspecific morphological variability and similarity has generated widespread taxonomic confusions. One of the most emblematic cases is that of C. ehrenbergiana (Klotzsch) Liebm., considered a very ample taxon encompassing both C. pallida Torr. and C. tala Gillies ex Planch. Given that both latter entities are clearly distinguishable in the field, a morphological and taxonomic revision was performed. After extensive sampling, a detailed morphological study and through a Principal Components and Conglomerates Analysis, it was concluded that what is considered as C. ehrenbergiana in Argentina, actually involves three entities: C. tala, C. pallida var. pallida and C. pallida var. discolor Hunz. & Dottori, and the rehabilitation of those taxa is proposed. The Variance and Similarity Analysis results support significant differences (p-value <0.05) between groups. The following relevant taxonomical characters were established: habit of the individual, bark pattern, pubescence of leaf blades, nerves and petioles, stipular spines/spiny branches, domacia aspect and abundance. Besides, some C. pallida specimens are morphologically intermediate between both varieties, and therefore their proper identity will be clarified through the use of molecular tools.