19 September 2016

Sycamore White Spot

White Spot on Sycamore, Rheola

Sycamore White Spot is a fungal disease caused by the Hyphomycete, Cristulariella depraedans. It becomes evident in late summer and autumn and often brings about a premature defoliation of Sycamore (Acer pseudoplatinus). It is rarely mentioned or illustrated in books on fungi, although Tar Spot of Sycamore (Rhytisma cerium) which causes black blotches on Sycamore leaves often is. The white-ish or pale buff spots give the leaves an attractive pearlescent appearance from a distance. Close inspection of the upper surface of the leaves shows how the fungus eats away at the superficial layer of leaf cells (the epidermis) to reveal the vascular network below.

Cristulariella depraedans colonies on upper surface of Sycamore leaf

From below, the characteristic dark border around the fungal colonies is clear to see.

Cristulariella depraedans colonies observed from lower surface of Sycamore leaf

Sycamore White Spot seems to be very common this year. Every Sycamore I looked at today in Rheola was infected with C. depraedans, while none had any Tar Spot infections. Perhaps the very humid summer we've had in South Wales this year has provided ideal conditions. It will be interesting to know if others have noticed an increase in the incidence of this easily recognised fungal disease.

11 September 2016

Garden beetles

Three plastic cup pitfall traps left overnight in the garden last night produced three species of carabid beetle and two harvestmen.
Nebria brevicollis & Synuchus vivalis
Pterostichus madidus
Odiellus spinosus

15 August 2016

A Chinese Stowaway - a mystery mugwort.

Yesterday (14/8) evening, I visited the North Dock dunes LNR on the north shore of the Burry Inlet, Llanelli to look for moths at dusk. As part of that activity, I was targeting (ie `beating` and `sweeping`) various plants which I know have micro-moths associated with them - tansy, sea campion, marjoram etc. I also looked at stands of common mugwort Artemisia vulgaris, which has a particularly attractive tortricid associate that I`d already recently recorded at nearby Machynys.
Looking through the pathside vegetation on the saltmarsh edge of the main track that goes along the whole length of the dune spit on its eastern side, I noticed a very tall plant (approaching 6ft) which, from afar, I did n`t recognise. 
        Above: the mystery Artemisia standing proud of surrounding vegetation.

Upon approaching it, I immediately thought `mugwort again` but I then also noticed that the leaves were very linear indeed. Thinking that this was unusual, I collected a few leaves to compare with common mugwort which, conveniently, grows on the other (duneward) side of the path and they were indeed noticeably different.
                Above: typical leaves of the mystery Artemisia (left)  and A. vulgaris.

Driving away from the site, I vaguely remembered that there was an alien mugwort called Artemisia `verlot-something` (I could n`t remember what it was exactly). At home, it  seemed that it was possibly Artemisia verlotiorum `Chinese mugwort`. However, further inspection suggested that it did not quite `fit` that species, with some characteristics being intermediate. `Googling to see if hybrids existed between vulgaris and verlotiorum I came across several references including the useful paper in Watsonia 23:139-147, (2000).
I wonder if it possibly may be - but I`m not completely convinced - the hybrid A. wurzellii? Incidentally, this paper comments that `there is no convincing evidence that the hybrid arose in situ` [at any of the sites where it was recorded]. I have collected material which I`ll pass on to Richard Pryce, the Carmarthenshire BSBI Recorder for his `processing`.
                                       Above: another view of the problem plant.

The tongue-in-cheek `stowaway` element in the title alludes to its possible origin at this site. The dune spit is actually developed on a foundation of dumped copper slag from an 18th-19th Century nearby copperworks, augmented (or preceded) by loads of ship ballast from the early days of the port of Llanelly`s trade (the old anglicised spelling of Llanelli as used in that period). About 18 months ago, there was much work undertaken to strengthen the seaward side of this dune spit and, to allow access by large lorries and earth-moving vehicles, the track was widened, disturbing the copper slag/ballast core in the process. Possibly, the plant originated from long-buried seed or was brought it by the large lorries and other vehicles from elsewhere?
I`m not sure about the true identity of the above plant but it is distinctive and differs from A. vulgaris which frequently grows elsewhere at this site. Perhaps it is just well grown because of its position on the damper uppermost part of the saltmarsh transition - but the leaves are consistently narrower. I need to check out other plants of A. vulgaris growing on richer soil elsewhere in case I`ve been `misled` into a botanical `wild goose chase` by the broader leaves of plants of this species on the dunes. Hopefully, we`ll find out in due course.
The grid ref of the plant (obtained from `find a grid reference` where I estimate it was on an aerial photo - so it may not be 100% accurate) is SS49833 99022.


30 July 2016

Amazon Wildlife

Pale Galigale (Cyperus eragrostis) in dry pond bed along Amazon Road

The new Amazon Road which connects with the recycling plant near Elba Crescent has some interesting man-made habitats which include a small pond, grasslands and disturbed ground. I have watched the development of the vegetation around the pond for the last few years. It dries up every summer and last summer the muddy floor had a large population of Red Goosefoot (Chenopodium rubrum). There was also a small patch of  Pale Galingale (Cyperus eragrostis), an attractive member of the sedge family that likes to grow in places that are flooded in winter and dry up in summer. This year there was no sign of the Red Goosefoot, but Pale Galingale is now dominating a large area of the pond. Pale Galingale is an alien in the British Flora, first recorded in the wild on Guernsey just over a hundred years ago. It is remarkable that this tropical, American species is now turning up in suitable habitats all over South Wales and is surely responding to climate change.
Several large populations of Yellow Bartsia (Parentucellia viscosa) occur in suitable places along Amazon Road. This is a designated Scarce Plant Species in the British Flora and a Biodiversity Action Plan species in Neath Port Talbot. It has been known from the Jersey Marine area for over 50 years but it has benefited greatly from the recent creation of open mosaic habitats.

Yellow Bartsia (Parentucellia viscosa) in open mosaic habitat along Amazon  Road

A few years ago Barry Stewart found some Oak-leaved Goosefoot (Chenopodium glaucum) in disturbed habitat around Swansea Docks. This very scarce achaeophyte has only been recorded a few times in Glamorgan (or anywhere else in Wales) and Barry's excellent record was the first for a long time. So I was glad to see it growing on some disturbed, weedy ground near the Amazon site with a number of other archaeophytes such as Black Nightshade (Solanum nigrum) and Fat Hen (Chenopodium album). Oak-leaved Goosefoot may not win any prizes in a beauty contest, but it has  a distinct appearance with its small, oak-like leaves which are mealy-grey underneath. It's good to know that these archaeophytes are still able to survive in disturbed ephemeral habitats in our area.

Oak-leaved Goosefoot (Chenopodium glaucum) in waste ground near Amazon

Leaves Oak-leaved Goosefoot

Before the Jersey Marine Amazon site was cleared for construction, there was a large area of birch/willow woodland which supported a rich community of fungi, thriving colonies of Common Wintergreen (Pyrola minor) and one of the largest populations of Yellow Bird's-nest (Monotropa hypopitys) that I have ever seen (hundreds of plants). A small colony of Common Wintergreen survives, but the rest has gone. The apparent loss of Yellow Bird's Nest ( a UK Biodiversity Action Plan Species) here is lamentable. Nature moves on!

28 July 2016

Hare's-tail at Port Eynon

Hare's-tail growing abundantly on the dunes at Port Eynon (SS469851) 4th June 2007
Charles' recent discovery of Annual Beard-grass Polypogon monspeliensis near Crynant reminded me of my encounter with the superficially similar Hare's-tail Lagurus ovatus at Port Eynon back in 2007. The species was growing in abundance through one section of dunes with many thousands of plants, and although I've been back to the site in more recent times (casual visits rather than dedicated searches) I've failed to find it since. The Crynant Annual Beard-grass and the Port Eynon Hare's-tail are the only records we have of these attractive casuals in West Glamorgan.

27 July 2016

Annual Beard-grass

Annual Beard-grass (Polypogon monspeliensis) in roadside verge, Crynant

Recently I came across this attractive grass in a disturbed roadside verge near Crynant. Annual Beard-grass (Polypogon monspeliensis) is a south western European species which reaches its northern limit as a native species in south east England, where it grows on coastal grazing marshes. However, it also occurs sporadically as a casual alien species on disturbed (waste) ground and rubbish tips further west in Britain and as far north as Scotland. It is quite rare in Wales, but it has appeared in the docklands of Newport and Barry in the past. Outside its native range it probably originates as a bird seed alien or garden escape. It also occurs as an alien in North America where it is sometimes called Rabbit's-foot Grass and has pest status. The plants shown here were growing with a respectable cohort of weedy species such as Scented Mayweed (Matricaria recutita), Spear-leaved Orache (Atriplex prostrata), Lesser Swine-cress (Coronopus didymus), Shepherd's Purse (Capsella bursa-pastoris), Redshank (Persicaria maculosa), Hoary Mustard (Hirschfeldia incana) and others. Beard-grass is so named because of the long awns that are so conspicuous in its inflorescence,

 Inflorescences of Annual Beard-grass (Polypogon monspeliensis) with long, bristly awns


19 June 2016

A few more bugs for the BAY-less!