BIOSTATISTICAL STUDIES OF WESTERN-EUROPEAN ALLOGAMOUS POPULATIONS OF THE EPIPACTIS-HELLEBORINE (L) CRANTZ SPECIES GROUP (ORCHIDACEAE)

Multivariate methods using morphological characteristics were applied to the study of 23 western European allogamous Epipactis populations b elonging to five taxa in the E. helleborine group and two taxa in the E. atrorubens group. The study concentrated on four recently described , not yet widely accepted, taxonomic entities of the former group and on the identification of discriminant characters. Several vegetative a nd floral differences allow proper discrimination of E. helleborine s. str., E. distans, E. neerlandica, and a subgroup composed of E. tremo lsii and E. lusitanica. A more detailed analysis was needed for the la tter two, for which the differences are chiefly vegetative. The five t axa also possess distinctive ecological characteristics and, consideri ng the respective geographical ranges and sympatries, can be regarded as independent species.