Abstract.DELFORGE, P. - Gymnadenia rubraWETTSTEIN 1889 and the taxonomy of
apomictic Vanilla Orchids [Natural. belges92 (Orchid. 24):
The history and context of the description of the Red Vanilla
Orchid, Gymnadenia rubra, apomictic, and its allied, G. stiriaca, G.
dolomitensis, G. minor, G. bicolor, and G. hygrophila, all apomictic
too, are evoked. The descriptions of the last 4 species, recently
published, are based almost exclusively on the subjective evaluation of
some morphological characters without explanation of the basis for
these statements nor attempts to investigate the extent to which these
characters might be prone to environmentally induced variation.
Furthermore, the morphological characters used for the delimitation of
these 4 species do not work in many cases in the field. Taxonomy of
agamous complexes present in 47 families of Angiosperms has always been
considerated as very difficult. Surveys of apomictic species in
numerous genera have found significant levels of intrapopulation
genetic diversity, frequently a paradoxically high level, which is not
significantly different from those of congeneric sexual relatives. As a
result, the morphological intrapopulational plasticity of apomictic
species can be larger than specific differences between two closely
related species, because of differential responses among genotypes to a
temporally and spatially fluctuating environment. This mecanism
contributes to the maintenance of within-population genetic diversity
and renders determination very difficult. More objective
interpretations of morphological and genetical data of apomictic
species complexes have led to grant species status to groups of related
apomictic or partly apomictic variants rather than to individual
morphotypes. As it seems that G. minor, G. bicolor, and G. hygrophila
constitute only morphotypes (or ecomorphs) of G. rubra, they are better
treated as forms. They are formally named here G. rubra f. minor, G.
rubra f. rosea, and G. rubra f. hygrophila respectively. As the rank of
variety seems more appropriate for G. dolomitensis, it is named G.
rubra var. dolomitensis.
Gymnadenia, Gymnadenia sectio Nigritella, Gymnadenia rubra, Gymnadenia
rubra var. rubra f. hygrophila (W. FOELSCHE & HEIDTKE) P. DELFORGE
comb. et stat. nov., Gymnadenia rubra var. rubra f. minor (W. FOELSCHE
& K. ZERNIG) P. DELFORGE comb. et stat. nov., Gymnadenia rubra var.
rubra f. rosea (C. BOILLAT & V. BOILLAT) P. DELFORGE comb. nov.,
Gymnadenia rubra var. dolomitensis (TEPPNER & KLEIN) P. DELFORGE
comb. nov. Taxonomy, apomixis.