The biggest surprise of the season (so far) is the double re-appearance of the nationally scarce Althaea officinalis (marsh mallow) in the county, with one site at Otmoor and the other by the Thames near Shiplake. Usually a plant of brackish marshes at coastal sites, A. officinalis was reported by Druce as appearing in a ditch at Long Meadow near Iffley/Oxford in the 1830s, and was more recently recorded as a casual from the Oxford tip. Where these newly recorded plants could have come from is a mystery. The Otmoor plant appeared a few years following the cutting of a hedge by a ditch on the RSPB reserve, and could have appeared from buried seed. Perhaps more plausibly as it is growing by a footpath, it could have been accidentally introduced from a visiting birder (it also grows at RSPB Minsmere). If it were an introduction, it seems odd that it should appear simultaneously with another plant at the other end of the county, but then it has never been known from Otmoor and is the habitat at either site right?
