Saturday, 3 June 2017

Between the Ure and the Nidd, between the Skell and the Laver - An Antipodean Alien

1. Context:- Historical and geographical 

To skip  the rambling details you can click here for the point lower down the post where I say what this intriguing plant is.
I grew up in Ripon -- with the purple moor (I now realise) of Dallow Gill hazily visible in the distance from the top floor of the science block at school.

On 31 May I drove from Grewelthorpe and Hackfall Woods, SE230775  (having visited the woods with Nidderdale AONB Volunteers Botany Group) back to Pateley Bridge - skirting the side of these moors - and driving over the bridge at Skell Gill where we visited to paddle so many years ago.

From this moor, 270m,  at the very flat water divide between the Skell and the Laver (which join up at Ripon) I could look back down on How Hill

View of How Hill from Dallow Moor.
The Skell flows into Ripon, just to the left of How Hill
I parked and drank the lemonade drink (that I had humped round all day with the AONB Botany group, down and up the hills of Hackfall). Looking back north north east I was amazed at the gentleness of the slope
View NNE: The Pennines slope gently down from west (left) to east

From the same spot looking south south west I was amazed at the gentleness of the slope. 

(Brimham rocks is only 4 or 5 km away to the SW, and the road at Brimham is also 270m, though the rocks rise a little higher) 

View SSW: The Pennines slope gently down (from west (right) to east.
The road is going over the water divide between the  Laver and Ure to the north (behind)  and the Skell  1/2 mile ahead

2. The plant

The land is managed for heather for grouse.

I inspected the road verges for interesting plants.

I found one that I did not recognise at first - "Do I need Poland and Clement - the vegetative key?" I thought. Then I realized it might be an invasive species - spread all the way along the road on both sides.  What looks like Agrostis -fescue grassland on either side of the road in the above pictures is mostly this new plant I had not seen before. It has pinnate leaves and looks a little like Pirri-pirri-burr -(an alien from New Zealand) - But it is not quite the same... Needs investigating.

I continued to Skell Gill bridge.

Bridge over the Skell
With Pertusaria corallina lichen

The Skell
There were at least six species of Sphagnum on the moist banks

 And here is the plant - with New Zealand Willowherb growing in the wetter banks of the road ditch.  I shall have to use Poland and Clement...

Or maybe it is Chamomile Lawn??


Keying out with Poland led me to the possibility of Cotula.
It was a plant with alternate simple leaves and deeply pinatifid, very slightly fleshy leaves, no hairs; It had buds that showed it was the daisy family,  It came out in Section PU in Poland.  Cotula coronopifolia  is the only daisy type plant in that section. I had a look on the internet at Cotula and "invasive species".  (C coronopifolia has yellow petals and is prostrate and grows in salty places, so it wasn't likely to be that species itself)

Keying with Stace, and internet picture searches, and dissection of the flower bud (Asteraceae) which had continued to grow in the plastic bag I had left it in, led me to Cotula australis - Batchelors buttons. 

Hmm, no  Cotula australis in this part of Yorkshire - surely this area has already been well surveyed.

3. Digression 

Note on Pirri Pirri burr. Pirri Pirri burr has  ball-like heads of hooked seeds (burs). It spreads on peoples shoes and animals. The two other places I have seen it are on Lindisfarne where it is a big problem and on Skipwith Common - both are nature reserves. But it has stipules. My plant does not.

You can buy Pirri pirri burr in shops. Plantlife consider that it should be a "Schedule 9" plant - Certain species of plants and animals that do not naturally occur in Great Britain have become established in the wild and represent a threat to the natural fauna and flora. They are put on schedule 9.

4. Further investigation

I was due to take Nidderdale AONB Botany group out to visit that road on Wed 14 June (the next day) . 
I emailed The local BSBI recorder, and I emailed Kevin Walker of the BSBI, who I knew would know the area I had visited.

He replied! Thanks.
Yes it is Cotula.. (but not Cotula australis) - It's not in our books! It is Cotula alpina.  This plant was reported to him by Linda Robinson  in 2009 .., and possibly first noted (though misidentified in c1978) in Nidderdale.. but there is more story to come.. .. that will be on another post

This was his first message to me: - 
"It is Cotula alpina from Australia. Linda Robinson first alerted us to it but I've traced records back to 1978 by Harrogate Naturalists. It is widespread on grouse moor tracks on east side of Nidderdale, North York moors and north of Ullapool. In all these areas it is spreading along tracks/road verges. It is a very rare rockery plant but we're not sure how it got from gardens to grouse moors!"

I have now read Linda Robinson's article on discovering it in 2009.

So - we were eight years late in discovering it.. I wonder how much it has spread since then - the verges on either side of the road are almost entirely this Cotula

Meanwhile, shortly to come are pictures of our day on 14 June:

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