Callitriche stagnalis Common Water-starwort

Callitriche stagnalis, Common Water-starwort, is the most commonly recorded Water-starwort in Britain, but it is probably confused with other Callitriche species, particularly Various-leaved Water-starwort (Callitriche platycarpa). Some important characters include its broadly winged fruits which are as long as broad, the presence of bracts on the youngest flowers, the occurrence of male and female flowers on the same plant and the spreading or recurved (but not reflexed) style of the female flowers. To differentiate it from Various-leaved Water-starworts you need to examine the wings of the fruit, the leaves and pollen very carefully, Common Water Starwort has much more broadly-winged fruits than Various-leaved Water-starwort and its rosette leaves are a pale, greyish-green colour. Also, overall, the leaves of Common Water-starwort are more uniformly broad. The most reliable character, however, is the shape of the pollen, which in Common Water-starwort is more or less uniformly spherical. The pollen of Various-leaved Water-starwort is bluntly triangular. Common Water-starwort is a common plant of poached pools that dry out in summer and also of shallow pools. It is less aquatic than Various-leaved Water-starwort and rarely occurs in deep water. It is common in West Glamorgan.

Native