Callitriche stagnalis - Water Starwort - (Callitrichaceae)

These submerged weeds are difficult to identify to species level because the leaf shapes vary with water depth and flow rate. Some are annuals and others are perennial.

Common Water Starwort

Common Water Starwort is illustrated here. In Wales, where this specimen was photographed, the River Teifi around Lampeter has several other startwort species including Callitriche hamulata, or Intermediate Water Starwort. These water plants are also widespread throughout the rest of the UK and in parts of Europe.

The flowers, which are minute, appear at the bases of the leaves from May to August, and the tiny, four-segmented fruits follow.