New Year's Day Plant Hunt on the Durham coast

Just sent in my list of species that I found flowering today for the BSBI New Year Plant Hunt (see bottom of this post), after walking the cliffs from Seaham to Hawthorn Dene on the Durham coast, 

Despite the mild winter so far it's not a very impressive list - just 14 species. For almost all of them, I'd be surprised if I didn't find them flowering at this time of year, with one exception. 

The only really interesting species in the list is yellow-wort Blackstonia perfoliata. There were scores of plants flowering around the old limestone quarry near Hawthorn Dene. Some were undoubtedly second generation plants that were progeny of individuals that flowered early last summer and these late bloomers have benefited from the mild autumn to reach flowering size and set seed, probably pollinated by small flies attracted to the yellow flowers. 

There were also some robust non-flowering plants that were undamaged by last night's frost and may well survive the winter, to flower very early in 2016. 

B. perfoliata, with it's annual life cycle and overlapping generations, could be a species whose fitness, in terms of overall annual capacity to reproduce, might be enhanced by warmer winters.

It seems likely that there might be at least five main types of plants that are in flower at this time of year:

1. Occasional mutants whose flowering control mechanisms for responding to temperature and/or daylength have been disrupted. A classic example might be the Glastonbury thorn mutant of hawthorn. A number of horticultural mutants e.g. winter-flowering pansies and primrose species fall into this category too.

2. The hangers-on: late summer/autumn-flowering species that continue to flower sporadically if the weather isn't too severe. In genetically variable species there are always likely to be some plants that are more likely than others to perform in this way.

3. Spring-flowering species whose blooming is genuinely brought forward by mild winters e.g spurge laurel, blackthorn and sweet violet

4. Species that have always flowered all year-round anyway and don't need any pollinators e.g. groundsel.

5. Species that might be showing an adaptive response, taking advantage of a changing winter climate. Species are only likely to benefit from this (i.e. have increased fitness, in the sense of leaving more progeny) if they have non-specific pollination requirements and yellow-wort fits this category rather well, since its yellow flowers are attractive to small flies, that are present even in winter and are active on milder days.

Species flowering at Seaham today:

Yellow-wort Blackstonia perfoliata
Wood avens Geum urbanum
Red dead-nettle Lamium purpureum
Ragwort Senecio jacobaea
Common daisy Bellis perennis
Sow thistle Sonchus oleraceus
Gorse Ulex europaeus
Winter heliotrope Petasites fragrans
Bramble Rubus fruticosus agg.
Dandelion Taraxacum officinale agg.
Groundsel Senecio vulgaris
Annual meadow grass Poa annua
Herb Robert Geranium robertianum
Ox-eye daisy Leucanthemum vulgare

Unusual Bloomers

Thursday's Guardian Country Diary is about this November-flowering dog rose that we found blooming amongst the rose hips, on a bush growing at Hawthorn Dene on the Durham coast.

The recent record-breaking spell of warm late-autumn weather has extended the flowering period of many plants and even induced some to flower for a second time. Recently we've found holly in bloom and also elder flowers opening alongside berries on the same branch, as well as the usual late-blooming suspects like yarrow, hogweed and clovers. 

This rose was one of two fully-open flowers on a bush covered with ripe rose hips on leafless stems. None of the other roses around it had any flowers. Presumably this individual plant was genetically predisposed to reacting to warmer-than-normal November temperatures. I've seen burnet rose flowering at Christmas in a couple of mild winters but have never seen this kind of behaviour in dog roses.

It seems unlikely that these late flowers will produce seeds because there were no bee pollinators around and the plant had almost no leaves to provide sugars to fill seeds, unlike ...

... the late-flowering yellow-wort that was blooming at the same site. These flowers were being visited by small fly pollinators that are quite numerous at this time of year and especially attracted to yellow flowers. This species is a fast-growing annual and I suspect that the late-bloomers that we saw might have been second-generation plants themselves, benefitting from the unusually long growing season this year.

Like many annuals, yellow-wort is one of those plants that can grow large and carry scores of flowers in good soil conditions but can also survive in tiny pockets of soil, producing very small plants with just a few flowers and setting seed rapidly when conditions are challenging. Thanks to those fly visitors, the tiny plants flowering in limestone fissures that we found might well produce some viable seeds before winter finally bites.

Two early-autumn flowering members of the gentian family on the Durham coast

Both of these members of the gentian family (Gentianaceae) were in flower near the limestone quarry south of Seaham on the Durham coast today.

The delightful little felwort, Gentianella amarella ..........

......... also known as autumn gentian .......... and

....  yellow-wort Blackstonia perfoliata, whose leaves are perfoliate - i.e. they have no stalk and the plant stem runs right through the centre of them.

...... and now for the good news.....

If you let it, taking an interest in natural history could be very depressing because so much that is written about our flora and fauna in the press seems to be unrelenting bad news. The abysmal weather in the early part of this summer  produced also sorts of hyperbolic headlines of the disastrous/cataclysmic/catastrophic kind about its likely impact on birds/butterflies/insects and almost everything else in the natural world - and it's undoubtedly true that it has been a bad summer for all of these (although it's important to bear in mind that over last few thousand years there have been periods of far more adverse climatic conditions that our wildlife experienced and rebounded from: like investments, rates of growth in populations of living organisms can go down as well as up, all the time). The natural world isn't a natural history museum, it's a living, constantly evolving interplay between organisms.

Anyway, last weekend we happened to notice a positive effect of the wet early part of the summer, when we took a walk along the cliff tops between Dawdon and Hawthorn Dene on the Durham Coast Heritage Path. The summer wild flowers there seem to be flowering more spectacularly than I can ever remember. I have a theory as to why this might be so, and it's all down to the rain. 

The cliffs are porous magnesian limestone which is free-draining. In a 'normal' summer the surface soil dries out quickly and the plants suffer from moisture stress, so they flower quickly while they have the chance, when they are quite small. This year, with plenty of water, the well-watered vegetation is unusually lush and as a result the flowers are truly spectacular. So, without further ado, here are some examples....

Drifts of meadowsweet in the gullies on the cliffs and ....

.... forming a backdrop for devil's bit scabious which .....

...... includes some exceptionally fine examples ..... although this one looks a tad unusual - very short bracts under the inflorescence and it looks like it might be male-sterile, judging by the tiny stamens.

... along with field scabious .....

... flowering in profusion in the meadows at the end of Hawthorn Dene ...

... where there are some fine specimens of giant bellflower.

I suspect that alkaline soil might be the reason for the very blue hue of the tufted vetch on the cliffs but .... 

... this unusually pale betony plant (normal flower behind) is probably a genetic mutation.

Bloody crane'sbill always puts on a good show ....

.... and this year centaury has done well too, with some very floriferous plants ...

This is hemp agrimony .....a major constituent of the taller vegetation while .....

.... hoary plantain is blooming down amongst the grasses.

Plenty of knapweed Centaurea nigra, alongside the ....

.... greater knapweed Centaurea scabiosa.

Drifts of marjoram aka oregano (crush the leaves and sniff for a tantalising hint of Mediterranean cuisine!)....

Spear thistle already running to seed ....

.... likewise agrimony, producing its little bell-shaped hooked fruits ....

Yellow loosestrife ....

.... and some wonderfully robust specimens of yellow-wort, with its strange glaucous, stalkless leaves.

In dry summers yellow-wort, which is an annual, is often a stunted plant and only produces a few flowers - but this year some plants have responded to the rain with a wonderful display...

... and the North Sea provides a fine backdrop for the floral spectacle ....

..... and for haymaking ....

An Industrial Legacy

Just south of Seaham on the Durham coast (see http://cabinetofcuriosities-greenfingers.blogspot.com/search/label/Durham%20Coastal%20Path) there’s a little bay called Hawthorn Hive, reached by a steep cliff path. The Magnesian limestone is constantly eroding here, creating small landslides that bring down the flora and fauna from the cliff tops to beach level. There it’s completely sheltered from the south-westerly winds that blow across the cliffs for most of the time, so the display of wild flowers and butterflies at the back of the beach is simply wonderful. Pictured here, from top to bottom, are carline thistle, yellow-wort and rest harrow. This is one of a number of delightful bays along this coast that were once used for dumping colliery waste, that are well on the way to being fully restored to their former glory, but ironically the narrow zone of biodiversity at the base of Hawthorn Hive’s cliff depends on past industrial pollution. Here coal dumping created a raised beach that stops the waves from reaching the base of the cliffs (bottom two photographs). With rising sea levels, once the sea finally sweeps away the last of the colliery waste (and it’s eroding quite rapidly now), the days of the present cliff base flora and fauna will be numbered. There’s a little more about this at http://www.guardian.co.uk/environment/2009/aug/06/seaham-coast-colliery-waste