An Abundance of Atriplex

Lockdown has taken me in all sorts of interesting botanical directions this year. It has given me time to look at certain groups more closely, and resolve past problems. Of course, the end of recording like a mad thing for the New Atlas has also helped with this!

Everyone knows Oraches (Atriplex) can be very variable, and this is most regularly commented on in relation to the coastal species. Especially comments and opinions around whether or not intermediate forms are hybrids or distinct defensible taxa. Much less is said about the inland forms and, until the last volume of Sell & Murrell came out, there was little in print (at least easily accessible print) to help with this.

I've tried to get to grips with these taxa previously but have struggled with the key, but finally things have clicked and I hope my experience can help others look more closely. I suspect there is something very interesting going on (at least in terms of differences between the first two forms illustrated below), but more records are needed to confirm this. This was brought home to me solidly this weekend, when botanising around Swillington (VC64). An arable field there had swathes of Common Orache (Atriplex patula), with 100's of var. erecta growing with abundant var. patula. Clearly very different from each other, and the latter well into fruit while the former was some weeks behind. They may hybridise, but clearly they are more than capable of maintaining themselves.

Atriplex patula var. erecta

This seems to be the commonest variant, matching Peter Sell's opinion. A stiffly erect plant that is markedly heterophyllous (lobed broad leaves, and linear to lanceolate ones with no lobes). Some leaves can also be more or less dentate, with this varying between plants. This plant finally made sense when I thought to look at some sheets in Herbaria@Home, and found some reliable ones collected by the Rev. Augustin Ley in the late 1800's. Historically this plant was treated as a species (Atriplex erecta) and in my humble opinion I think they had a point. It would be interesting to know what the genetics tell us.

Atriplex patula var. patula

Common in arable fields. The leaves are redolent of 'baby spinach' (if you don't know what that is then try the salad aisle the next time you are in the shops) i.e. dark green, thick and succulent. Leaves grade along a common theme, and are clearly not of two distinct types. Most keys do not work well for this variant (were they built with reference to var. erecta?) as the bracteole character could take you to Spear-leaved Orache (Atriplex prostrata), but the bracteoles are far too large for that species.

'

Atriplex patula var. linearis

I only found a few plants of this delicate, diffuse and spindly variety (there are a couple more varieties also to be found, one of which forms prostrate circular plants). Compared with the above varieties it is more delicate with much more uniformly narrow leaves (to 15mm, rarely a little wider). The leaves can have a basal pair of lobes but, unlike the first two, are never toothed. My memory of my childhood on the farm in Oxfordshire is that it was common in arable fields down south ( I knew 2 to 3 forms of Common Orache even if I could not name the varieties concerned).