Taxonomic studies in Avena abyssinica and A. vaviloviana, and some related species

Abstract

This paper reports the use of micromorphologic attributes taken from the lodicules, epiblasts, and disarticulating scars for purposes of circumscription of the taxa associated with the names A. abyssinica and A. vaviloviana and their F1 hybrids, and also A. barbata. Furthermore it is shown that the epiblast can serve as a good marker to distinguish between the hexaploid A. byzantina and the tetraploid A. abyssinica, especially for those cases where previously only the chromosome number could have served this purpose. From the micromorphological findings, some cytological data, and plant distributional data, the author decided to regard A. abyssinica, A. barbata, and A. vaviloviana as separate species. The status of these species in previous classifications is compared with that proposed here. The many different classifications used in the past are attributed to the fact that no reliable diagnostic morphological markers were discovered by previous workers. A connection was discovered between A. occidentalis of the Canary Islands and the tetraploid abyssinian oats and a close relationship in this vicarious group is speculated.