grandiflora ssp. rosea (Mutel) Casper (1962)
French botanist Pierre Auguste Victor Mutel
described already in 1830 a
population from the French Savoyen Alps that grew along the Grand Canal
near Grenoble, which differed in the flower form and flower coloration
from the typical P. grandiflora. In 1962 the German
botanist S. Jost Casper
ranked these populations, that were found in the meantime at other
locations with the same stable characters, as a subspecies under the
grow either directly on wet, vertical limestone cliffs
or in wet meadows along small streams. This subspecies of P.
grandiflora was found only in the two French departments
Haute-Savoie and Isère in altitudes between 650 and 1400 m above sea
subspecies differs from ssp.
grandiflora by its smaller flower, by its white to pale
rose-pink coloration of the corolla lobes, by the rose-pink tube
covered with a reddish veination, by the straight and awl-shaped spur
(mainly of a dark red or red-violet colour) and by the short,
oval-shaped lobes of the upper calyx lip.
the following principles are respected a successful
cultivation of P. grandiflora ssp. rosea
in a cold greenhouse or outside is possible. As with all temperate
butterwort species you should keep the substrate wet all year round,
with a reduced watering during the period when the plants have formed
the hibernaculum, otherwise there is a risk that the plants would rot.
To overwinter plants in a cold greenhouse temperatures between
and 5° C are recommended. Higher temperatures up to 10° C will be
tolerated by the plants, but there is a higher risk that fungi would
develop on the plants and may harm them and plants will probably form
summer leaves very early in the year. To overwinter the winter buds in
a fridge is also an option, but then I would recommend treating the
hibernaculum with a fungicide against mould. If plants are cultivated
outside, a permanent freezing and thawing of the substrate should be
prevented, as then the hibernaculum could move outside of the substrate
and would then dry out. Cultivation in pure peat is possible. Good
cultivation results can be achieved also by using pure vermiculite. The
latter has the advantage that even under wet conditons the substrate
still has enough larger pores to secure a good aeration of the roots.