Seed morphological diversity of Egyptian Allium L. (Amaryllidaceae) and its taxonomic significance

Abstract

Allium L. (Amaryllidaceae, Allioideae, Allieae) has disputed generic delimitation and species boundaries, compounded by the proliferation of the species' synonyms. This study provides for the first time a comprehensive ­description of the seed morphology of native, endemic, and near-endemic species in Egypt and addresses the significance of seed traits for infrageneric classification. Twenty-two Allium taxa belonging to four subgenera and six sections were investigated using fresh or dry materials from their mature seeds. Thirty-eight quantitative and qualitative traits of the seeds' dorsal and ventral sides were investigated using stereomicroscopy and scanning electron microscopy (SEM). Statistical and multivariate analyses were performed. This work provides the first description of the seeds of 13 Allium taxa, including A. artemisietorum Eig & Feinbrun, A. barthianum Asch. & Schweinf., A. blomfieldianum Asch. & ­Schweinf., A. crameri Asch. & Boiss., A. desertorum Forssk., A. erdelii Zucc., A. mareoticum Bornm. & Gauba, A. papillare Boiss., A. roseum subsp. tourneuxii Boiss., A. sativum L., A. sinaiticum Boiss., A. spathaceum Steud. ex A.Rich., and A. trifoliatum Cirillo. This study reports for the first time a comparative investigation of dorsal seed surface traits against ventral traits, revealing conspicuous differences for most species and highlighting the most informative diagnostic seed traits for ­distinguishing taxa. Allium subg. Allium L. has a broader range of variation than any of the other subgenera.