Taxonomy of the Elymus scaber complex (Triticeae: Poaceae)

Abstract

Elymus L., following Love’s (1984) genomically defined system, consists of about 150 species which are widely distributed throughout the world. Eight species: E. apricus, E. falcis, E. enysii, E. multiflorus, E. rectisetus, E. sacandros, E. solandri and E. tenuis, are currently recognised in New Zealand, and three taxa, E. scaber var. scaber, E. scaber var. plurinervis and E. multiflorus, were recorded from Australia. Elymus rectisetus was occasionally also considered to be present in Australia. There were taxonomical problems about the number and the circumscription of Australian taxa.

The morphology of 102 samples representing the full range of Australian taxa was examined. Thirty-seven morphological characters were subjected to a phenetic analysis using cluster analysis and Semi- Strong- Hybrid multidimensional scaling (SSH). RAPD analysis was carried out on a sub-set of Australian samples. Characters dealing with the rachilla, callus and palea apices were revealed to be taxonomically informative. These characters were subsequently used to augment a large character set in order to investigate Australian and New Zealand taxa.

Five taxa from Australia are formally recognised: E. fertilis sp. nov., E. multiflorus, E. plurinervis comb. nov., E. scaber subsp. scaber and E. scaber subsp. rectisetus comb. nov. Furthermore, E. rectisetus sensu Love et Connor ( 1982) from New Zealand is confirmed to be identical to E. scaber subsp. scaber, and E. enysii is shown not to belong to Elymus. Both agreements and disagreements were found between the results obtained from morphological and RAPD data sets. The final taxonomic conclusions were attained based on comprehensive application of all information.