Sunday, 15 February 2009

Welcome Hellebore

A walk around the Downs south of Banstead this morning showed what twelve inches of snow does to the vegetation. Although most of the trees and scrub had sprung back after losing their load of snow, the grass and other herbaceous plants have a sorry, flattened, grey-brown appearance. The bright green shoots of recovery are not yet showing and the local rabbits seem to be having a hard time, as you walk past they carrying on browsing when normally they disappear the minute you appear.

This almost total greyness was only interrupted by the welcome presence of Stinking Hellebore (Helleborus foetidus). This plant never fails to please at this time of year with its bright green buds and flowers standing out like a beacon amongst the gloom. There is a small colony here and the plants all show the flattening effect of the recent snow and damage to the foliage. The flowers are not quite open yet but when they do they show a rim of red to the petals (the picture on the left was taken a few years ago). The flowers produce a considerable amount of nectar and must prove a valuable source of food for the early emerging bees and other insects.

This species normally starts to flower at this time or even earlier and is fairly common along the North Downs and elsewhere in Britain on chalk and limestone. It is one of two Helleborus species native to Britain, the other being Green Hellebore (H.viridis) that usually flowers a month or so later. Green Hellebore is much less common on the Downs, the nearest colony to here I know of is near Dorking and where it does occur it is usually much less conspicuous. Although a less showy plant, it can form large colonies such as shown in the lower photo of plants growing on the banks of the River Wye near Symond's Yat.

Monday, 9 February 2009

Absent parasite

The countryside surrounding Banstead provides a fair range of habitats with one of the commonest being woodland/copses containing a high proportion of Hazel (Corylus avellana)trees often showing evidence of ancient coppicing. Indeed my own and neighbours gardens in the middle of Banstead contain large old coppiced Hazels with associated flora including Ramsons (Allium ursinum) and and Lesser Celandine (Ranunculus ficaria).

Now whenever I come across Hazel coppice especially in the spring I look forward to the possibility of seeing Toothwort (Lathraea squamaria) a parasitic species most commonly on Hazel although it has been known to attach itself to Ulmus species if it can find any! Being an obligate parasite it contains no chlorophyll and the flower spikes appear straight out of the ground with the flowers varying in colour from white through to deep purple. It is a rather attractive plant that often suffers from weather damage because of its early appearance from March onwards. I have seen it growing in many places in the UK, usually on limestone and locally have seen it on Epsom Downs and Headley Heath (top picture). So far however I have failed to find it in or around Banstead despite the abundance of its host. I shall keep looking.

A couple of years ago we visited a well known colony of this plant in the Purbecks, Dorset. We were lucky enough to find plenty of plants in unusually pristine condition and this enabled us to appreciate their true beauty and to get some half decent photos (bottom two). Who knows, one day Banstead!

Interestingly a friend of mine managed to get this species to grow on Hazel in his garden by sowing seed directly onto a damaged Hazel root. I think this is more commonly done succesfully with the other (introduced) species to be found occasionally in this country, L.clandestina. This species is native to SW Europe and is parasitic on Salix and Populus species.

Tuesday, 3 February 2009

Banstead Downs' own Early Purple Orchids

With the snow lying thick and not so even outside, I have been going through a few pictures and came across some of Early Purple Orchid (Orchis mascula). I find this species intriguing. When I first was interested in wild flowers I knew it only from the damp woods of the Weald in Surrey, Sussex and Kent growing on clay (see picture at bottom of plants growing near Ockley, Surrey). Here it grows quite tall with relatively spindly spikes of flowers and leaves with variable degrees of spotting but rarely very intense. In places it forms carpets that in numbers come close to competing with the Bluebells growing at the same sites.

In later years, I discovered the species growing out in the open on more northern and western limestone at places like Hutton Roof Crags or the Purbecks. At these sites the species takes on a very different appearance, altogether more robust and striking with dense flower spikes seemingly more intensely coloured flowers and leaf spotting. On casual acquaintance they could be a totally different species.

In the back of my mind I had assigned all sorts of physical reasons for this difference in habit suggesting they may be mutually exclusive . I now realise that this is an artificial distinction and virtually anywhere you can see a wide range of "compactness". It still remained however that I had never seen O.mascula growing out in the open on the Downs or any other chalk site in the South East

Therefore I was astonished just a few years ago when someone showed me a colony of this species growing on Banstead Downs, astonished if only for the fact that I had been walking past them for years and not noticed them. There are about one hundred plants growing in a small area alongside one of the fairways on the golf course, on the edge of and just into light scrub and my excuse is that they are surpringly easy to miss.

In appearance they are more robust than the woodland plants, not surprisingly considering the very dry habitat and they are notable for the wide variability in flower colour, pattern and shape.

I assume the colony has been there for a long time but I have had real difficulty finding anyone who can provide definitive information. Whether it is a relic of a much larger population I do not know. If there is anyone out there with more knowledge about them, please let me know.