Infrageneric grouping of Allium - the Gatersleben approach

Infrageneric grouping of Allium - the Gatersleben approach

Hanelt, P. Book author
Hammer, K. Book author
Knupffer, H. Book author

Gatersleben Institute of Plant Genetics and Crop Plant Research

1992

p.107-123

SB339.A4H3

Infrageneric relations within Allium are a rather untouched field. The Gatersleben Allium project has been established to get a better understanding of the taxonomic relationships between the different groups of the genus. Based on a large living collection (more than 200 species), diverse methods have been applied for the study of morphological, anatomical and cytological characters, serological reactions, growth rhythms and eco-geographic data. The evaluation of these results has been synthesized into a preliminary proposal for a new infrageneric classification (see Table 1): Six subgenera are accepted (Bromatorrhiza, Rhizirideum, Allium, Melanocrommyum, Caloscordum, Amerallium). Two larger ones (Rhizirideum, Amerallium) are most variable: although perhaps not strictly monophyletic they must be recognized as basic groups of the genus on account of their primitive character states. These are according to comparative studies among others: perennial rhizomes with long-lived roots, several shoot generations per year and the formation of many leaves (functionally undifferentiated into storage and assimilating ones and characterized by vessels arranged in a single row and by a well-differentiated assimilation tissue), seeds with a smooth to granular testa and straight anticlinal cell walls, simple septal nectaries, bi-ovulate locules, symmetrical karyotypes with primary basic numbers and the lack of endogenous dormancy periods within the growth cycle. The heterogeneity of the mentioned two subgenera is strengthened by results of a first numerical analysis. The other subgenera are clearly derived groups, and mostly characterized by synapomorphies. Strongly derived sections however occur also within Rhizirideum and Amerallium (e.g. sect. Campanulata and sect. Briseis. respectively). The divergence between the x=8 branch of the genus (the majority of its species) and the x=7 branch (subgen. Amerallium) must have occurred very early in the phylogenetic history of Allium. Their disjunctive holarctic distribution is one of its indications. The less known subgen. Bromatorrhiza occupies an intermediate position between these two cytologically and anatomically well elimited (and serologically confirmed) groups but it may prove to be an artificial assemblage of different phylogenetic lines. [AS]

The genus Allium - taxonomic problems and genetic resources; Proceedings of

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