Various-leaved Hawthorn (Crataegus heterophylla)

Various-leaved Hawthorn (Crataegus heterophylla) is one of those frustratingly elusive species, you know its out there but can never seem to find it. To the extent that it starts to feel a little mythical. This is not helped by the lack of any more than a handful of images for this obscure species, which is only known in cultivation and as an introduction. Pretty much every image that there is to be found is on Wikimedia Commons. The best of which is this one:

I did find a bush a few years back in the Dales that I thought could be this species, but I lost confidence in the ID and decided that it might just be very atypical Common Hawthorn (C. monogyna). Similarly, there have been other bushes in hedgerows around Woodlesford (VC63) that seemed close to this species, but with leaves that were too deeply lobed. 

So it was a milestone moment this year, while scrutinising a hedgerow on the edge of arable fields at Lowther Lake (VC64) that I had not previously looked at closely, that I found amongst an array of other taxa a bush that could only be this species. It is of planted origin, but is now well established and is fruiting well.

It is important to look at the flowering shoots, which have leaves of variable shape but with lobes in no greater than the upper two fifths of the leaf blade, a distinctive narrowly elongate outline, and a markedly cuneate base. The leaves on non-fertile shoots are very different and contrast strongly with the leaves on fertile shoots. The fruits also seem slightly smaller (less plump) than those of Common Hawthorn, with reflexed narrow (longer than wide) sepals.

This discovery also provided a frame of reference for other local hawthorn bushes that have been bugging me for several years. These have the distinctive lobing and narrow leaf shape of this species, but are too deeply incised. I now think these are hybrids between Various-leaved Hawthorn and Common Hawthorn (Crataegus x subheterophylla). They seem more frequently planted than Various-leaved Hawthorn, matching observations of other hybrid hawthorn taxa and other 'look-alikes' and 'false natives'. Growers seem incapable of keeping their stocks pure, and hybrid swarms seem to be increasingly propagated and distributed for planting in wild settings, for ecological mitigation and for nature conservation. Eastern Hawthorn (Crataegus x subsphaerica) is another example of this, and one that I have flagged previously as being widely over-looked and under-recorded. We may not like it, but increasingly I think we will need to recognise that hawthorns are (at least in many lowland settings) best determined in fruit. The species and hybrids are so variable in foliage, and the hybrids generally occupy a complete spectrum between both parents. 

A few examples of what I consider to be good candidates for Various-leaved x Common Hawthorn below.

Postscript to the above:

Having found my 2017 photos from Stainforth in the Yorkshire Dales (VC64) and looked at them again, I think this hawthorn also can only be Various-leaved Hawthorn. If anything its an even better candidate than the above. How it got onto Goat Lane would seem the bigger mystery. I can only assume it has bird sown from either an amenity planting somewhere lower down the valley.