Drawdown

The silver lining to this year's prolonged dry spell is that it is a great year for looking at the flora of the drawdown zone around Skelton Lake (VC63 and 64). Most years, summer rain raises water levels again before things have had long enough to develop to their full potential.

Of course, my first port of call was to have the annual check on Grass-poly (Lythrum hyssopifolium). I could only find one, perhaps too dry for germination, but it might have a late flush with a bit of rain.

Grass-poly

It seems to be a really good year for Golden Dock (Rumex maritimus), and their are carpets of thousands of Mudwort (Limosella aquatica). Both present in the same corner of the lake as the Grass-poly as well as along the eastern shoreline.

Golden Dock

Carpet of Mudwort

Moving on, there was a cobble bar exposed in the river. In the absence of the usual dog walkers and swans it was worth an explore, and proved very rewarding. There were a surprising number of Tomato plants (Solanum lycopersicum), at least until considering the location downstream of the outfall for the Knostrop sewage works. Also, large numbers of Fig-leaved Goosefoot (Chenopodium ficifolium) growing with Red Goosefoot (Oxybasis rubra) and the best find Striped Goosefoot (Chenopodium strictum agg. - this would key to C. striatum using Sell & Murrell and is the prevailing form locally). Like most goosefoots, the development of the stripes and red coloration on the latter species seems a bit hit and miss in Yorkshire, I suspect we just don't get enough heat for long enough.

Tomato

Striped Goosefoot

Another good find in the river was the riparian form of Pale Persicaria (Persicaria lapathifolia subsp. lapathifolia) - easily mistaken for a more exotic species if not aware of how different it looks from the typical arable field form (subsp. pallida). It comes up around Skelton Lake most years and it is always nice to meet this graceful plant again, with its drooping flower heads, spotty stems and 'knobbly knees'. Nearby there was an unusually pale form of Linseed (Linum usitatissimum), also well as a few Marsh Dock (Rumex palustris).

Pale Persicaria

Linseed

Back over to the lake, there were two final treats. Sunflower (Helianthus annuus) and Grey Fat-hen (Chenopodium pseudoborbasii). The latter is a controversial Sell & Murrell segregate, but I've seen this small species a lot this year and it seems to be widespread, distinct/distinctive (more so than the widely accepted Swedish Fat-hen, Chenopodium suecicum) with its grey colouration and leaf shape, and relatively uniform in morphology. Albeit, in the latter case, its worth noting there are two forms - single stem (f. pseudoborbasii) and branching from the base (f. ramosa). The two forms often occur in isolation, but sometimes they can be found together.

Sunflower

Grey Fat-hen

Rumex crispus subsp. robustus

Working near Rossington, Doncaster (VC63) a couple of weeks back my eye was drawn to a large Curled Dock (Rumex crispus) growing on the hedgebank. It looked unusually tall (>1.3m) and robust, with broad leaves, a huge inflorescence, large tepals and an usual deep green coloration. Then I saw another and then another. So I collected some hoping it might be the poorly known, and presumed non-native, subspecies robustus.

Further research confirmed these initial thoughts, with the tepals clearly in the size range for this subspecies (being 5-6mm wide). To be on the safe side I pressed it and sent a sample to Geoffrey Kitchener, the BSBI referee for the genus. Thanks to Geoffrey for confirming my identification.

The ever invaluable Alien Plants of Belgium website provides a little more detail on this subspecies, including a useful key as follows:

1a. Valves ca. 5-5.5 mm wide, slightly cordate at base, ca. as wide as long, with a single inconspicuous tubercle, ca. 1.5 mm long. Lateral inflorescence branches slightly spreading, not tightly appressed to the main axis. Leaves lanceolate to broadly so, with weakly undulate margins. Plant tall, much exceeding 100 cm === subsp. robustus

1b. Valves ca. 3.5-5 mm wide (longer than wide), truncate at base, with 1-3 tubercles, the larger ca. 2 mm long. Lateral inflorescence branches often tightly appressed to the main axis. Leaves narrower and more distinctly undulate at margin. Plant smaller, rarely exceeding 100 cm (native) === subsp. crispus

The presence/absence of a well developed tubercle seems unreliable for ID purposes, with some disagreement in this in other references. Even on one plant this seems relatively variable. Geoffrey also advises that there can be a zone of overlap in tepal width, so my main advice would be to consider the plant as a whole. Does it otherwise look like typical subspecies crispus (likely to be somewhere nearby as a point of comparison)? If not, chances are its the real deal.

Chenopodium rubrum var. pseudobotryoides

It really has been an exceptional year for investigating the drawdown zones of my local lakes (Skelton and St Aidan's, VC64) in south Leeds. Even now, at mid-September, they have been continuing to throw interest with the best numbers for several years of Golden Dock (Rumex maritimus) and Nodding Bur-marigold (Bidens cernua).

The latest surprise, as of last weekend, was the abundance of the dwarf decumbent form of Red Goosefoot (Chenopodium rubrum var. pseudobotryoides) at St Aidan's. September really is its season. I've blogged about this plant before when I found it at Eccup Reservoir, and this is the first time I have seen it since then. I believe this may be its first appearance at St Aidan's, certainly I have not noticed it in previous years.

While the evidence is slim there does seem be some indication that this variety has a genetic basis, and that it is not just a response to environment and season. Certainly it is hard to believe it could suddenly turn into the typical plant. I think points in its favour are that when it occurs it does so with great uniformity and often in its 100's, and it coexists with late germinating plants of the typical form which are very small but otherwise perfectly typical.

The stem is characteristically a vivid red, but the leaves are not always this yellow, I think these plants have either been hit by recent cool nights or are running to seed. Given it leaves it so late into the season to appear, it probably lives fast and dies young.

Finally, I can't really mention Golden Dock without including a photograph. So ...

Marsh Dock

Wetland habitats still maintain some interest at this time of year, providing a 'last hurrah' before winter. St Aidan's (VC64) proved this last weekend with good numbers of Marsh Dock (Rumex palustris) still going strong. This is not a species I remember seeing here before, and it may be that I have missed it because it peaks late in the season.

This species has a primarily Eastern England distribution. It is widespread but scarce in Huntingdonshire, but is exceptionally scarce in VC64 where it seems to be restricted to wetlands along the Aire Valley. I wouldn't be surprised if it occurs elsewhere e.g. in the Ripon area, and it may be overlooked because of its phenology and also because many of the wetlands it favours have no public access or only restricted access to marginal habitats.

Golden Dock at St Aidan's

With sunshine and blue skies today I thought it worth a late season trip to St Aidan's (VC64) to see if any of the Golden Dock (Rumex maritimus) rosettes seen earlier in the year had made it to flowering. I was rewarded with four plants, one of which was in peak bloom and worth photographing. This species was more abundant a couple of years ago, water levels and goose trampling haven't favoured it recently. I also wonder if the recent rapid spread of New Zealand Pigmyweed (Crassula helmsii) is also impeding germination.

Golden Dock is a rare plant in VC64 and is largely restricted to a few wetlands in the far east of the county. It is a little more frequent in VC31, but it is still a scarce plant of drawdown habitats.

Less attractive, but equally pleasing - at least to me and perhaps because it requires a little more investment in time to go beyond a species-only identification - was the scattering of the wetland specialist subspecies of Greater Plantain (Plantago major ssp. intermedia) along the drawdown zone. While identifications should always be confirmed by counting the number of seeds in a pod (>15 seeds is diagnostic) it is very distinct once known, with its typically diminutive size, pointed leaf tip, toothed and hairy leaves, and usually decumbent inflorescence. It is also much more specialist in niche than its more competitive and weedy sister (ssp. major), normally being associated with disturbed damp ground, and often only germinating and flowering late in the season.

A final lucky find was a second location for Greater Soft-rush (Juncus pallidus), again doing its best to blend in with the Club-rushes (Schoenoplectus spp.). The following photo is pretty ropey (I should have got my camera out rather than using my phone), and it does nothing to show the size of the plant which was easily as tall as me.

Suspect Sorrels on Stocking Fen

Before the HFFS meeting at Monks Wood, I took myself off to Stocking Fen (VC31). My primary aim was to investigate the Woodland Trust plantation of Muchwood and Mary's Wood, but ultimately this turned into a much more rewarding trip onto the "fen" down as far as Ramsey Cemetery.

Corners of some of the arable fields had been put down to wildflower grassland, no doubt under a Stewardship grant, and were carpeted with Lady's Bedstraw (Galium verum), Fodder Bird's-foot-trefoil (Lotus corniculatus var. sativus), Oxeye Daisy (Leucanthemum vulgare) and Common Knapweed (Centaurea nigra agg.). However, what caught my eye was a colony of an enormous Sorrel. This turned out to be Garden Sorrel (Rumex acetosa ssp. ambiguus), sometimes treated as a distinct species (R. rugosus).

Garden Sorrel, as in this case, can tower to 1.5m tall, has long floppy pale green leaves and large repeatedly branched panicles. My photographic skills let me down, so here is a photo borrowed from the Manual of the Alien Plants of Belgian website.

The other good find of the day was Dwarf Fool's-parsley (Aethusa cynapium ssp. agrestris) scattered along arable margins with Treacle Mustard (Erysimum cheiranthoides) and Sharp-leaved Fluellen (Kickxia elatine).