Drosera rotundifolia L. - Round-leaf sundew
Maybe it is one of the most well-known among the so-called carnivorous plants. It grows on peaty substrata, where nitrogen and phosphorus, the main nutrients, are scarsely available.
It is characterized by delicate leaves set in a rosette, with round-reniform lamina and 1.5 cm long peduncle. On the upper pagina they are endowed with reddish glandular hairs, which are longer near the edges. These hairs have sticky glands whose function is to capture small insects and digest them through specific enzymes. The floriferous stem - without any leaves - is 10-15 cm high and it can bear up to 10-15 white small flowers.
It has a small root system. The species grows in habitats which are rich in water but not subject to intense dessication, derectly on simple peat or moss carpet. The species is typical of acid peat bogs at an altitude from the sea level to 2.000 metres. It is also present, however, in the alkaline fens of the resurgence area in Friuli, where it grows epiphytally on Schoenus nigricans and Molinia caerulea tufts above the maximum calcareous ground water level. The species is mainly present in Italy in the hills and in the mountains, as the locations of the species on the plain have been destroyed by reclamation of marshland. The resurgence specimens are therefore very interesting from the environmental conservation viewpoint, even if they are reduced in numbers and sites, both for their sea level locations (10-30 metres) and for their alkaline habitats characterized by calcicole species.
G. Bolognini ©