Monday, 30 March 2020

Wild flower of the month: March: Purple Saxifrage

Purple saxifrage on Pen-y-ghent,
 March 1997
Image: K. J. Walker
While we’re all confined to our homes and gardens, this seems like a good time to revive our Wild flower of the month feature and focus on favourite flowers we’ve seen over the years and which we always remember with affection.

Many of you will know Kevin Walker, BSBI’s Head of Science, from his many scientific papers, the BSBI books he’s co-authored, the field trips he’s undertaken to carry out research, the presentations he’s given... It’s easy to forget that Kevin, like all botanists, is driven primarily by a love of our wild flowers! So read on for Kevin’s account of a trek he undertook to see an iconic plant which flowers in spring:    

“One of my most memorable days botanising was my first ever trip to see Saxifraga oppositifolia (Purple Saxifrage) on Pen-y-ghent in Yorkshire in 1997. Although I had seen it on Ben Lawers a few years before this was the first time I’d encountered it at its best in the spring. I had walked Pen-y-ghent many times, usually as part of the ‘Three Peaks’ challenge, but this day was different. I was only interested in purple jewels that adorn the crags some 50 metres below. The species had almost mythical status to me. It was the plant of the mountains and tantalisingly described by Raven & Walters (1956) in Mountain Flowers as ‘the most spectacular element in the flora of the upper parts of Ingleborough, as also of Pen-y-ghent to the west…which makes as vivid a show here as anywhere else in the British Isles.’

Purple Saxifrage on Pen-y-ghent,
 April 2010.
Image: K. J. Walker
“So here it was in England, growing within an hour’s drive of my home. I had only the vaguest idea of where it grew. Having read Jeremy Robert’s (1991) excellent account of the alpine flora of Ingleborough I knew it grew in abundance above the ominously named Black Shiver – a deep chasm created by a huge landslip. This though was on Ingleborough, the second highest of the Three Peaks (723 m) and the first place it was ever recorded in the British Isles in 1668 (Pearman, 2017). A botanist friend had told me that it was easier to see on Pen-y-ghent; ‘just head up the motorway and when you hit the first line of limestone crags start looking – you won’t miss it’. That sounded easy enough but knowing the geology of the area I was a bit confused. Surely the limestone was lower down where the pavements protruded from the lower slopes. Wasn’t everything above that point just acid?

“So on the penultimate day of March, 1997 I set off from Horton-in Ribblesdale with the brooding hump of Pen-y-ghent in my sights. There was virtually nothing in flower on the way up, except for snowdrops and daffodils along the village stream, a few sprigs of Cottongrass in the bogs, the brilliant bluey-purple hue of Purple Moor-grass florets just emerging on the limestone. And then, just where the track cut through the first line of crags, there it was just below the path - vivid purple cushions amongst the drab greens and browns. On closer inspection the flowers were exquisite with the delicate pink petals enclosing a garish ring of orange anthers. The trailing red stems held tight clusters of leaves, resembling tiny cabbages dipped in sugar due to the deposits of lime on their tips. 


Purple Saxifrage amongst the snow
 on Pen-y-ghent in March 2020
with the distinctive summit of Ingleborough
 in the far distance
Image: Peter Kerr
"I found lots more that day on the line of limestone crags that stretch for almost a kilometre along Pen-y-ghent’s north-eastern flanks. These ended in a large amphitheatre where the piercing call of a male peregrine drew my search to a close as it warned me away from its nest.

“Since then I’ve been back periodically to pay my respects, either to Pen-y-ghent or Ingleborough where it grows on the same band of limestone below the summit. On a beautiful spring day last April, we went as a family to Pen-y-Ghent and then on to the adjacent Plover Hill. As we descended towards Foxup Beck we hit the same band of limestone, here forming a jumble or small outcrops, boulders and flushes. Amongst the rocks were the distinctive leaves of its close relative Saxifraga aizoides (Yellow Saxifrage), another rare alpine confined to a only few sites in Yorkshire, a few fronds of  Asplenium viride (Green Spleenwort) and another limestone speciality of the area,  Alchemilla glaucescens (Silky Lady's-mantle). 


Purple saxifrage on Svalbard
Image: under licence from Robert Harding
 
"And then there it was – glistening in the spring sunshine – a few patches of Purple Saxifrage in what appeared to be a new site. Alas on checking the BSBI’s Distribution Database I saw that someone had recorded it in the same tetrad – but at least I had put some flesh on the bones of the location.

“Purple saxifrage is a notable for a number of reasons. It is without doubt one of our most attractive mountain flowers adding a welcome splash of colour to the drab locations it usually inhabits. It is also by far the earliest mountain plant to flower, usually poking through the snow in March (exceptionally February), providing nectar for early flying insects. 


Leaves of Purple-saxifrage: 
can you see the lime-exuding pores? 
Image courtesy of J. Crellin/ Floral Images
https://www.floralimages.co.uk/page.php?
taxon=saxifraga_oppositifolia,1
"It is also exceptionally tolerant of frost and wind growing throughout the arctic and on higher mountains farther south in North America, Europe and Asia. It inhabits some of the coldest regions on earth, including the most northerly known patch of vegetation in the world at 83°N in Peary Land (Scott, 2016). It also has the highest altitudinal record of any plant occurring at an elevation of 4,505 metres (14,780 ft) in the Swiss Alps (Körner, 2011).

“To find it (once Covid-19 restrictions are lifted) your best bet will be to head for base-rich crags in the mountains of Scotland, north-west Ireland, North Wales or the Lake District where, if you are familiar with the distinctive leaves with their lime-exuding pore at the apex, you’ll find it at any time of year. 

"But to see it at its best I suggest you make a pilgrimage to Pen-y-ghent next year in late March or early April so you get to see it at its best against a backdrop of snow and limestone. Follow the motorway route up the southern shoulder and look for it on the first set of crags – like my 26 year-old self - you won’t be disappointed!”

1 comment:

  1. see also
    https://www.youtube.com/watch?v=0vTBLKOtapw&t=58s

    ReplyDelete

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