Wednesday, 29 July 2020

Large-toothed Hawkweed

These difficult times continue to reap botanical rewards on my local patch, an area I had thought well botanised but which is still throwing regular surprises.

Today's treat on a post-work stroll down to St Aidan's Nature Park was Large-toothed Hawkweed (Hieracium prominentidens), a species I had found previously in nearby VC63. Happily, I now have it in my VC as well, and its a second county record. The only other record is from York.

A nice simple species to ID, given it obviously sits in Section Sabauda, has eglandular phyllaries and long (to 12mm in this case) teeth on the leaves.

Monday, 27 July 2020

Unusual Creeping Buttercup

A little while ago Mark Spencer (VCR for London) put a note in the BSBI England Newsletter asking recorders to keep their eyes open for a very robust (the leaves are up to hand-sized) glabrous form of Creeping Buttercup (Ranunculus repens) with an association with tidal watercourses. It needs more research, but Mark advises that it is currently being recorded as var. glabratus.

Luckily I had read the Newsletter prior to a trip to Keadby, North Lincolnshire (VC54). So when I was on the banks of the River Trent in just the right habitat and found just such a plant my brain went 'ping'. A few photos (see below) via email to Mark and the ID was confirmed.

I'm sure Mark would welcome a few more records, as well as observations on how well it flowers and sets seed (early impressions are it is not very good at doing either). There is an awful lot of suitable habitat between Keadby and Mark's records along the tidal River Thames, so it might prove widespread.

Sunday, 12 July 2020

Coatham Dunes (VC62)

A work trip gave me the opportunity to explore the large sand dune system at Coatham, part of Teesmouth & Cleveland Coast SSSI. It is a fascinating site where open mosaic habitats (developed over historic deposits of lime rich slag from the former steel works) and garden escapes blur into a full succession of dune habitats, from grey dunes on the landward side to a strandline community at the top of the beach.

Plants that caught my eye, and sometimes my nose, included:

The famed (see British and Irish Botany) plant of Hart's Pennyroyal (Mentha cervina) at the edge of a pond, one of just a handful of known locations in Britain. Unfortunately it was not in flower at the time of my visit.

The margins of the pond supported good numbers of Knotted Pearlwort (Sagina nodosa), always a nice plant to find. These plants were prostrate and therefore probably var. moniliformis. A trip later in the year would likely confirm, as the large buds forming now should start to drop off to give rise to new plants.

Within the pond was a large population of Horned-pondweed (Zannichellia palustris). These plants had fruit on obvious stalks (1.5mm long, clearly apparent with the naked eye) from a common peduncle and are therefore, based on Stace 4, subsp. pedicellatus.

Everywhere within the dunes and on the slag deposits was the dinky coastal form of Lady's Bedstraw (Galium verum subsp. maritimum), always a treat to catch in full bloom.

Perhaps one of the most exciting specialities of this dune system is Purple Milk-vetch (Astragalus danicus), a species holding its own further north but increasingly rare and patchily distributed in England.

Equally exciting for me was this curiously short, multi-stemmed (branching from base) and broad-leaved centaury. This meets published descriptions for the very poorly recorded and known sand dune form of Common Centaury (Centaurium erythraea var. fasciculare). Thanks to Tim Rich for confirming my identification from photos. See the BSBI Handbook and an earlier analysis of variation in Common Centaury in Watsonia for further information. The pale flesh-pink flowers may or may not be relevant, depending on what other recorder's find in the field.

Another nice coastal plant is the dwarf dune form of Lesser Meadow-rue (Thalictrum minus subsp. arenarium). Some would have you believe this isn't a genuine entity. Bluntly, I don't believe them. Having previously seen its enormous rhizome system exposed by the wind; this is clearly a dune specialist and an important sand binding species at that. It would be interesting to know what the genetic evidence says about the validity of this species.

My dabbling in hawkweeds continued with a chance to examine the known population of Uig Hawkweed (Hieracium uiginskyense), present in huge numbers in the dunes.

Several of the dune slacks were fragrant with the scent of carnations, traceable to plants of Marsh Fragrant-orchid (Gymnadenia densiflora). This species packs a real punch.

Equally fragrant and stunning was this escaped Honeysuckle (Lonicera periclymenum var. periclymenum 'Serotina') at the roadside.

To end with another garden plant. I am going to stick my neck out and say this is the hybrid lilac (Syringa x hyacinthiflora), although I would have been happier if I saw it in flower.  Long cultivated, I suspect this hybrid is overlooked elsewhere. This bush was notable for its more shrubby form and stubby heart shaped leaves.

Saturday, 27 June 2020

Townclose Hills SSSI (VC64)

Making the most of sunshine and a day off work I decided to walk over to Kippax and see what I could find at Townclose Hills SSSI, a fabulous remnant of unimproved limestone grassland affording great views over the lower Aire Valley. I wasn't quite sure what I would find, as the season seems to be whipping on at a rapid pace this year, with Butterfly-bush (Buddleja davidii) unbelievably in full bloom at the end of June. Thankfully, recent rain seems to have reinvigorated increasingly stressed flora, and grassland habitats at least are about where they should be for the time of year. Certainly, the grasslands of the SSSI were a carpet of flowers, with plenty to see. Highlights included:

Carpets of the native form of Kidney Vetch (Anthyllis vulneraria subsp. vulneraria), strictly prostrate to prostrate-ascending on weak stems.

Masses of Greater Knapweed (Centaurea scabiosa var. scabiosa), an uncommon plant locally.

Good swathes of Yellow-rattle (Rhinanthus minor subsp. stenophyllus), a subspecies more typical of calcareous fens further south but less fussy in Yorkshire where the local climate is more accommodating.

Perforate St John's-wort (Hypericum perforatum) which many will not consider that exciting, but I'm increasingly of the view that its not that common. I suspect it is widely over-recorded, especially in Yorkshire, for its hybrid Des Etang's St John's-wort (Hypericum x desetangsii). Recorder's shouldn't assume Perforate St John's-wort unless they have not checked the sepals carefully for the absence of teeth. By default it is therefore a plant that should only be named when in flower.

Plenty of Clustered Bellflower (Campanula glomerata) just starting to come into bloom.

With time to indulge this spring, and with an exceptional new BSBI Handbook to accompany Vince Jones' regional monograph (criminally under-printed by the Yorkshire Naturalist's Union), I've been dipping my toe into hawkweeds. One of the commonest locally, and earliest flowering, is Southern Hawkeed (Hieracium argillaceum). There was plenty of this in the grassland on steep slopes.

Moving down slope to the wooded margins of the SSSI provided:

Orange Whitebeam (Sorbus croceocarpa)

The largely sterile hybrid between Dewberry (Rubus caesius) and Raspberry (Rubus idaeus) i.e. Rubus x pseudoidaeus.

And, surprisingly, a highly scented hybrid Mock-orange (Philadelphus Lemoinei Group).

Into the woodland proper was a welcome plant of Soft Shield-fern (Polystichum setiferum), an uncommon species in the lowlands to the east of Leeds but one which is increasingly being found in small numbers in woodland habitats.

Thursday, 11 June 2020

Highlight of My Year So Far

This rather nondescript image has to be my best find of the year so far. You are looking at a close-up of the buds of a Wintercress and the tips are hairy. So, after several years of (if I'm honest) half-hearted searching, I have finally found Small-flowered Wintercress (Barbarea stricta).

I found a few plants today at the edge of an osier bed near Ulleskelf. I wouldn't be surprised if there are more locations to be found in that part of the county.

This also happens to be the first record for VC64 since 1975, and that previous record was the first since the 1800's. I'm so glad I checked for hairs!

Wednesday, 10 June 2020

Barbarea vulgaris subsp. arcuata

I last saw this variant of Wintercress (Barbarea vulgaris) in 2017 and had been starting to doubt myself. So I was glad to find a colony at the weekend, within a kilometre of my previous record, at Skelton Grange in Leeds (VC64).

This is a taxon that seems to have passed British botanists by in recent years, but Google suggests that it is widely accepted in mainland Europe. In particular, studies in Denmark have concluded that it is genetically distinct from subsp. vulgaris, and that it also comprises two genetically distinct forms (one with glabrous leaves, as per my plants, and another with hairy leaves). Whether the genetic differences justify recognition at subspecies level is perhaps debatable.

Sell & Murrell provide a description of this plant (as var. arcuata), but it is not too challenging to identify once you are certain of the species identification and it is in fruit. Subsp. vulgaris has more or less erect fruit orientated close to the alignment of the stem (and also perhaps more densely arranged as well), whereas subsp. arcuata has widely spreading fruit +/- curving upwards.

Subsp. vulgaris seems to be common everywhere, while I suspect subsp. arcuata may be of introduced origin (at least in Yorkshire). Photographs of both are provided below. There are also several informative herbarium sheets of subsp. arcuata in Herbaria@Home, for example.

Subsp. arcuata

Subsp. vulgaris.

Saturday, 6 June 2020

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.