Especie, variación biológica y especiación en Cladophora

PARODI, E.R

ACTA BOTANICA BRASILICA

SOC BOTANICA BRASIL

Lugar: Sao Paulo; Año: 1998 p. 223 - 233

0102-3306

Cladophora, which comprises aproximately 230 species is the largest genus of Cladophorales. Its ramified conformation makes it different from other genera of Rhizoclonium and Chaetomorpha with which, however, it is often mistaken. Cladophora is formed by an heterogeneous group of species of troublesome identification due to the poor definition of its diagnostic morphological characteristics. These features are well variable under the influence of environmental factors. There are well known international reviews but it is surprising that none of them coincide in the results they show. From Kützing up to now, reviews on this genus have been focused on such characteristics, yet due to its difficult observation, other features concerning its life cycle, karyology, etc., have not been taken into account. Results on statistical analyses carried out in Argentine populations indicate that the ploidy level in each population is kept constant and invariable. This was observed independently of: i) the fact that the morphological variation curve for different conditions was different for each ploidy level and ii) those environmental factors that modify the aspect of plants. All this has led me to postulate that the ploidy level can be considered as a discriminating taxonomic parameter, which could be accurate and objetive as species level.