Autumn recording

Rosa sherrardii at Meadow Farm. The main features visible are the forward-pointing sepals and strong straight prickles.

A full press, product of looking at roses at Meadow Farm

With the coming of the season of mellow fruitfulness, I have of late been thinking about all those brightly-coloured berries, drupelets, drupes, haws, hips and pommes in hedgerows and scrubby places. As readers familiar with my interests will anticipate, this has mostly focused on roses, but I have also been scratching my head over hawthorns and having a go at brambles. This blog post is about what I have been finding this autumn.

Roses were the main target for a recording meeting I ran at Meadow Farm Nature Reserve in Blackthorn. The highlight was Rosa sherardii (Sherard's downy-rose), a predominantly northern and western species which has largely disappeared from our area (see map below). Gareth Knass recently found it on the downs in the VC22 part of modern Oxfordshire, but except for the one bush at Meadow Farm I am not aware of any confirmed recent records for VC23. I have only otherwise seen the hybrid with R. canina from VC23 (R. x rothschildii, e.g. at Sydlings Copse). Gareth has taken many wonderful photos of roses — you can see his images of R. sherardii here.

We also found the hybrid between R. canina (common dog-rose) and R. micrantha (small-flowered sweet-briar) (R. x toddiae), which seems to be the first record for VC23 since 1930. There were also R. canina hybrids involving R. obtusifolia and R. tomentosa, which are quite widespread, as well as R. obtusifolia itself, which seems to be a more local plant. Other unusual hedgerow things included a big specimen of Salix cinerea subsp. cinerea, quite an uncommon plant in Oxon.

Oli Pescott and I spent an afternoon looking at roses around Hills Watlington, Pyrton and Shirburn on the Chiltern escarpment, another good area for roses (I blogged a couple of years ago about the rich rose flora at Aston Rowant). One of the most characteristic species is the downland rose R. rubiginosa (sweet-briar), which is quite uncommon as a native plant but is widely planted in hedgerows. With its strong apple smell, big hips with forward-pointing sepals and fiercely-armed stems it is one of the more straightforward species to identify. Oli and I also found a number of bushes at Watlington and Pyrton that at first looked like R. micrantha but that on closer inspection had a few small slender prickles (acicles) toward the ends of the flowering branches and irregularly-sized hips — these were the hybrid with R. rubiginosa. This was only recently found in Oxon, from Sydlings Copse, but these new finds suggest it may be more widespread.

Roses aren't all about hybrids, though they are certainly very common, and Oli and I saw a fine bush of R. tomentosa (harsh downy-rose) at the edge of Shirburn Wood. Recording for Atlas 2020 seems to have shown that this species is more common than previously indicated but that it is largely confined to the Chilterns, downy roses in the rest of the county being hybrids. We also had time to pay homage to the nationally scarce R. agrestis (small-leaved sweet-briar) at Pyrton Hill, which was rediscovered in the county in 2016.

Crataegus x subsphaerica at Watlington Hill (note the forward- directed sepals)

I have written a few times this year about about non-native shrubs that look similar to native species. So far, however, I have not introduced the non-native hawthorns. This was mainly because I hadn't seen many examples in Oxon, but this autumn I have seen quite a lot, and I encourage others to have a look while these things are at their most conspicuous. There are two taxa to look out for, Crataegus rhipidophylla (large-sepalled hawthorn) and its hybrid with C. monogyna which is called C. x subsphaerica and is the more commonly planted taxon (whether we also have the hybrid with C. laevigata I don't know). I have seen bushes of C. x subsphaerica that are pretty old so this taxon is likely to have been with us for a long time — there seems to be a lot of introgression with C. monogyna, which must explain why these things have been over-looked. Some bushes I have found can only have arisen from bird-sown seeds, so it may be widespread and not just confined to planted hedgerows.

As you will have guessed, the conspicuous features are the haws, which are larger than usual and the sepals stick up from the fruit. The haws are often a brighter shade of red than C. monogyna and more square-shaped. If you look at haws of C. monogyna you will see that the sepals are reflexed so that they lie against the haw and the sepals are short triangles with blunt tips — if you see a hawthorn with some haws with erect sepals and the sepals longer than wide and verging on acute, then you are probably looking at C. x subsphaerica. The leaves of this hybrid are similar to C. monogyna, though they are heterophyllous, and one can usually find some leaves that are broader toward the base and have more teeth, features of C. rhipidophylla. True C. rhipidophylla has leaves that look like similar to Sorbus torminalis (wild service tree). The descriptions and keys in the books suggest the differences are subtle but really they are quite striking, so don't be deterred!

The photograph to the right gives a good idea of what to look for. David Broughton has also blogged about hawthorns and has some good images — see here.