Mad Dogs ...

 ... and botanists go out in the mid-day sun on the hottest day of the year so far. Crazy, but I'm not one for wasting sunshine (I live in Leeds after all), especially after a spring lost to covid and excessive rainfall. So, I took one of my lazy weekend routes out along the shade of the river corridor towards Mickletown (VC63) and then back via St Aidan's (VC64).

Over the winter the Canal and River Trust had cleared a path through the woodland on the river bank near Lemonroyd Marina (VC63). This new route gave me the first good find of the day - several bushes of the irredeemably pungent Stinking Tutsan (Hypericum hircinum subsp. majus). A new species for my home patch.

Further on was a bush of hazel yet to be stripped of its nuts by voracious grey squirrels. This is one of the hybrids between the native Hazel (Corylus avellana) and the Filbert (Corylus maxima). This form could be easily mistaken for the latter but the involucre is not fully closed over the nut and consequently the nut is visible. This would key*, given the nuts are obviously longer than wide, to the form Peter Sell distinguished as Corylus avellana f. schizochlamys. However, the length of the involucre and the pronounced pinching over the nut means it is not a good match. It looks to have much more of an influence from Corylus maxima than is typical for this form.

Further on, and handy for comparison purposes, I found another bush likely to be part of this hybrid spectrum. Its a common form with very large nuts that are about as long as wide. Under Peter Sell's classification it can be called Corylus avellana f. grandis. Again the involucre exceeds the nut, which is a trait potentially derived from Filbert.

Out in the sun near Mickletown (VC63) there was an impressive mixed stand of Broad-leaved Everlasting-pea (Lathyrus latifolius), a garden escape. The pale-flowered plants seems a good match for the cultivar 'Rosa Perle', while the darker ones seem to be 'Red Pearl'.

Next to the pea was a distinctive bramble. This being, Slender-spined Bramble (Rubus elegantispinosus), a species that I learnt under lockdown last year. Baby steps with this genus. I remain ever hopeful for a regional handbook with photos.

The final treat of the day was the swathes of Hare's-foot Clover (Trifolium arvense) lining the track through St Aidan's (VC64). This species has exploded in numbers in recent years and is always a welcome sight.

* Update: I would modify this to accords with the pictures in Sell & Murrell. The descriptions seem back to front with the pictures. While it would be tempting to rely on the descriptions, I am also swayed by the description of var. grandis (the "big round nut" as originally defined in its latin diagnosis) in this account (European Journal of Taxonomy 409(409):1–45). This also seems to indicate that f. schizochlamys is not correctly applied in Sell & Murrell. All this is possibly academic given the more you look, the more variation can be found. It seems likely that these named forms only represent a tiny proportion of the true variation of this long cultivated tree, and at best are only loose groupings. I am increasingly inclined to take the stance of Alan Leslie in his excellent Flora of Cambridgeshire.

Interesting Trees

In sorting out photos from the last couple of months, I realise that I have quite a few photos of unusual trees that may be of interest to others. So for an easy post ...

2020 seems to have been an exceptional year for blossom, with a non-stop heady rush that was perhaps over a little too soon. One tree I always look out for a few weeks after the Wild Cherry (Prunus avium) flowers, is its double-flowered cultivar 'Plena'. This can be found in plantation woodland around the boundary of Oulton Park (VC63).

Near the above tree, is the double flowered cultivar of Horse Chestnut (Aesculus hippocastanum 'Baumanii'). I have been walking under this tree for years and never noticed it, but perhaps work commitments in a normal May mean I have never passed at the right time. I find its stumpy little candles rather unexciting, and that probably explains why its not seen more often. Foolishly I seem to have mislaid my photos, so here is an image from the Deepdales nursery website.

Unusual Sycamores (Acer pseudoplatanus) always catch my eye, and a favourite is f. variegatum 'Simon-Louis Fréres'. There is a fine tree in the churchyard at Swillington (VC64).

This handsome Common Whitebeam, at the edge of plantation in Water Haigh Woodland Park (VC63) is Sorbus aria 'Lutescens'. It remains white well into the summer when the young fruit are markedly pubescent.

In complete contrast this (I think) is Sorbus aria 'Majestica', with very large glossy leaves. It has been planted on the boundaries of Swillington Brickworks (VC64).

At the same location, Purple Filbert (Corylus maxima 'Purpurea') has self-sown from an unknown source. I think I am on safe ground (in the absence of fruit) with the ID given the excellent purple coloration, but most hazels encountered from introductions seem to be hybrid Kentish Cob types. Last year I found some of these with pale muddy purple leaves suggesting 'Purpurea' in the parentage.

The woodlands round the capped landfill at Newsam Green (VC64) include a few trees of Paperbark Birch (Betula papyrifera) amongst the Silver Birch (Betula pendula). These are only just reaching an age where the bark turns white, and the juvenile bark can be confusing.

Finally, to encourage more people to look at hawthorns as they come into fruit later this summer, here is a compare and contrast between the typically (not always, its not definitive) small-flowered Hawthorn (Crataegus monogyna) and its often large-flowered hybrid with Large-Sepalled Hawthorn (Crataegus rhipidophylla) i.e. Crataegus x subsphaerica. The hybrid is common and spreading locally, and probably elsewhere. Flower size is often a good way to pick out the non-native hybrid and its parent. However, the hybrid usually (but not always, some forms have clearly intermediate foliage) needs to be confirmed later when in fruit. Therefore, the large flowers may be the first indication that there is something potentially interesting to check again later in the year.