Opposite-leaved Pondweed is a once-common native water plant that has almost vanished from Hampshire’s chalk rivers and streams. Unrecorded populations may be hiding out there somewhere.
Where to look: ponds, lakes, ditches, and small channels near to chalk rivers and streams – especially around old mill sites, fish farms, or small feeder channels.
When to look: year-round, but most obvious April-October
Tips: Many paired, opposite, leaves >5cm. Grows in dense clumps of long, leafy stems, like a crowd of large, bright-green centipedes. Can grow with other plants e.g. Water-crowfoot, in still and flowing water.
If you think you have seen this plant, or would be interested in looking for it, please email Tristan Norton (Botanical Society of Britain & Ireland recorder for South Hampshire)