Morphological variation and distribution of cytotypes in the diploid-tetraploid complex of the genus Dactylis L. (Poaceae) from Algeria

Morphological and cytological characters were analysed among thirty populations of the genus Dactylis L. from Algeria, to understand its infraspecific diversity. Principal Component Analysis using quantitative characters allowed discriminating the tetraploid populations into two subspecies, marina (Borrill) Greuter, localised on sea cliffs, and hispanica (Roth) Nyman, very widespread. Some individuals of these latest populations formed a distinct group, identified as subsp. glomerata Hayek. Three diploid taxa are described in the literature: subspecies santai Stebbins & Zohary, castellata Parker & Borrill and mairei Stebbins & Zohary that are considered as prevalent in Algeria, distributed in Tellian Atlas, in forest ecosystems within mesophytic habitats. Canonical Discriminant Analysis on natural populations and on experimental cultures showed two main groups: the first group corresponds to subspecies mairei, with a narrow distribution; the second one exhibits a wide morphological variability and belongs to santai type. Based on this study, a key to aid in identification of the subspecies is presented.