Phenetic Similarity Patterns of Dioecious Species of Poa from Argentina and Neighboring Countries.

GIUSSANI L. M.

ANNALS OF THE MISSOURI BOTANICAL GARDEN

Año: 2000 vol. 83 p. 203 - 233

0026-6493

Dioecious species of Poa L. are mainly American with a total of 41 taxa in South America, 11 in North America, two in New Zealand and one species in the Peri-Antarctic Islands. South American species, considered within Poa section Dioicopoa, are found mostly in Argentina but occur elsewhere in Bolivia, Brasil, Chile, Paraguay, and Uruguay. The present treatment considers the phenetic variation of dioecious species of Poa in South America. Thirty seven taxa (34 species and three varieties) were examined, using numerical techniques. Multivariate analyses revealed a phenetic pattern among species based on linear relationships. Relationship of independent species as well as species complexes were established. As a consequence, new synonymy within most of these complexes, and a new variety, Poa rigidifolia var. ibari, are proposed herein. Bivariate analyses showed other non-linear patterns of variation. These results, together with univariate analyses, were used to select diagnostic characters. Sexual dimorphism was the major source of species variation and ranges for pistillate and staminate specimens were also calculated. An identification key for all taxa is also included.