A Tale of Two Picris

Hawkweed Oxtongue (Picris hieracioides subsp. hieracioides) is a native plant of calcareous soils being found on waysides, old quarries, chalk cliffs and downland. It is always a nice find in Yorkshire as it is not common up here. I have only seen it in VC64 growing on the old walls of Fountains Abbey (photo) and at Burton Leonard Lime Quarries Nature Reserve, although at the latter I must admit I did not determine the subspecies.

In recent years it has become known that several other subspecies also occur, or have occurred previously, in Britain. Most of these are non-native casuals. Generally the native plant can be distinguished from these by its longer branches and capitula on relatively long pedicels.

This came back to me today when I stumbled across a small colony of Hawkweed Oxtongue in Rothwell Country Park (VC63). This is not a location where the native would be expected, as this site is restored colliery land and was sown with a seed mix in the past. Sure enough this plant did not look quite right, with me having at the back of my mind that if it had some capitula near-sessile it was worth a closer look.

Of course coming home and revisiting the above photograph the differences are quite obvious. The current plant is subsp. villarsii (its synonym of subsp. umbellata is more descriptive). It has flowers arising in tiers on short branches, and the terminal inflorescence is sub-umbellate. Of course this latter trait was most obvious in the plant I decapitated for ID purposes, so I did not get a photograph in situ but I did manage to salvage a few photos later (see below). The phyllaries are meant to be blackish-green, this seems a bit variable and was not as pronounced as I was expecting from reading the key previously. It is probably less useful than the other characteristics of the inflorescence, but perhaps it darkens when pressed.