Pottering around with Polypodies

Polypodies (Polypodium spp.) are a group of ferns with something of a reputation for being a bit difficult to tell apart. Nevertheless, with a bit of experience it's possible to distinguish quite quickly between the two common species - P. interjectum (Intermediate Polypody) and P. vulgare (Common Polypody). In the field, this can be done on the basis of frond outline and the shape of the blobs of spore-cases (sori).

When in doubt, though, microscopic examination is needed, and so the other day I was working through half-a-dozen specimens that I had pressed during the last year.

One of these, which I had collected in March 2014 from Aberthin, I had initially thought might be a form of P. interjectum. It was pure ignorance on my part that I didn't suspect the much rarer P. cambricum (Southern Polypody) at the time, because it was a textbook example, with much wider fronds, and strongly toothed pinnae.

The very broad fronds of Polypodium cambricum...

...and the strongly toothed pinnae.

I'd not seen P. cambricum before, so I was quite pleased when under the microscope, it proved to have, as it ought to, only about 4-6 thick-walled cells on each spore-case (sporangium).

However, another well-documented feature peculiar to P. cambricum - the branched hairs or 'paraphyses' amongst the spore-cases - took a bit more effort to find. Although 'Stace' (edition 3) says these are >0.5mm long (and 'Flora Europea' says 0.6-1.2mm), you would have a job to see these with even a x20 hand-lens, as they're even thinner than the stalks of the spore-cases, and well-hidden amongst them. Colin Page's helpful 'Guide to Cumbrian Ferns and Fern-allies' says they are "very easily overlooked, especially when infrequent".

My persistence paid off, though, and I eventually found a couple of these hairs. I even managed to take a photo of one through my ancient brass microscope, by messing around with the settings on my Canon PowerShot. The surprising results of combining 19th-century and 21st-century technology!

One of the branched hairs that are diagnostic for Polypodium cambricum. Just above is the flap of a opened spore-case. The field of view is about 0.4mm.

P. cambricum is quite a local plant in Britain, with a southern/western, mostly coastal distribution. In Glamorgan there are a number of recent sites in the Gower, but apparently very few localised records from East Glamorgan. At Aberthin there are two metre-long colonies within a short distance of each other, growing on an old laneside bank made of limestone blocks - in firm agreement with its reported habitat of calcareous rocks.

One of the Aberthin colonies of Polypodium cambricum (left-most, brighter green clump), growing next to Polypodium interjectum (right-most, dull-green clump). Surely it's just a matter of time before the hybrid appears!

bugs in the evening sunshine

Sat in the garden with some tea close to hand, enjoying the last of the Monday evening sunshine and found myself watching the insects 'dancing' in the air. The dance extended as far as I could see over the neighbouring gardens and ended abruptly when the sun set.

There appeared to be two layers of participants. the lower layer included these two little beasties, approx. 5-10mm, who paused for a while on the wooden patio furniture.

The upper layer consisted of larger Tipulidae. These appeared to fly in more elaborate patterns and occasionally two would join and fly/tumble to rest on the garden woodwork.

Don't know what any of these are but it was mesmerising to watch.

Sallows at Cefn Mably Woods

The sallow blossom at Cefn Mably Woods (ST2184) was buzzing with insects this morning, but most of it was at the tops of tall bushes and impossible to view closely. However, one bush had been bent over by a conifer which had fallen on it, resulting in sallow blossom right by the track. On this one bush were nectaring Rd Admiral, Peacock and Brimstone butterflies, as well as numerous hoverflies. The best of these was the bumblebee mimic Criorhina ranunculi - an early spring species which favours sallow blossom.

Criorhina ranunculi (this photo taken in 2013)

Back home in the Llandaff North garden, I was pleased to see my first bee-flies (Bombylius major) of the year, as well as the lovely Red Mason Bee (Osmia bicornis) and a Small White butterfly.

Glamorgan Botany Group excursions

The Glamorgan Botany Group have six excursions planned for 2015, all in the eastern part of the county, starting on 25th April at Michaelston-le-Pit, Dinas Powys. Further details of the excursions are available on the website:

http://bsbi.org.uk/glamorgan.html

George

Spring in the uplands

In the hills above Dare Valley Country Park today, my first Wheatear of the year, as well as three Peacocks and a Small Tortoiseshell. The Peacocks were all in areas of gritstone scree, enjoying the warmth of the rocks (despite the lack of any nectar sources nearby).

Harvestman (2012) .... query

Looking through my 'anon' directory (lots in this!) and found this picture taken in my garage during August 2012. I was just starting to take an interest in bugs and things and was taking pictures of just about anything that showed itself in the house/garden. Didn't have a clue what it was and this is the only picture that was remotely in focus. I filed the image under 'oddities' and I haven't seen anything like it since.

I'm reasonably confident (now) that it must be a harvestman, and possibly Dicranopalpus ramosus - mainly because of the way the legs are held out from the body and the forked pedipalps.Weird looking thing though .....

Picture-winged Beauty

Yesterday, while up the mountain above Abernant, in the Cynon valley, I found myself amongst an area of heather and I decided to try a little beating to see what came out. I improvised a beating tray, using instead my small collapsible photographic reflector, white side up and amongst the groggy and grumpy spiders and bewildered springtails there was this lovely Picture-winged Fly. Anyone who was at this year's SEWBReC Recorders' forum will remember Dave Clements' interesting and entertaining talk on these. Based on what he said about the problems of identifying them visually, including from photos, I will make no attempt to identify this one from my photos, but I thought I'd post a poor photo of a lovely creature anyway.