Thursday, 18 April 2013

Irish Excursion

The week before last I made a multi-purpose trip across the Irish Sea beginning in Ulster with a weed survey at the Belfast Botanic Gardens.This small botanic garden is dominated by a curvilinear palm house, one of the earliest of its kind, dating to 1840.

'The Bulb Wing' of The Curvilinear House
at Belfast Botanic Gardens

The weed flora of the Belfast Botanic Gardens was mostly unremarkable though one rather nondescript plant was abundant and eluded identification for some time. It turned out to be Artillery weed, Pilea microphylla. This small creeping plant of the family Urticaceae is native to the Southern United States and the Caribbean. It has not been recorded naturalised in the UK but is known to be a glasshouse weed elsewhere. An interesting feature of this plant that is not noted in the books I have read is the presence of transverse translucent stripes across the leaves.  

Pilea microphylla, Belfast Botanic Gardens, April 2013 

Pilea microphylla,
Belfast Botanic Gardens, April 2013

The main purpose of my visit to Ireland, The Ecological Genetics Group Conference took up a few days following my visit to the gardens. The only small bit of botany I managed to squeeze in during the conference was on a field trip to the Giant's Causeway. No species of great interest were observed but the swollen overwintering rootstocks of Sea Aster, Aster tripolium among the basalt boulders were not something I had previously noted.  

Aster tripolium, Giant's Causeway, April 2013

When the conference ended I, my supervisor (Dr Natasha De Vere, NBGW) and another student (Tracey Hamston, Exeter) headed south to The Republic. Our first stop was The National Botanic Gardens of Ireland at Glasnevin. Here we meet with the Garden's head of science, Colin Kelleher. Our first order of business was identifying potential sites to visit over the next few days with a view to collecting Saxifraga rosacea for genetic work being carried out at The National Botanic Gardens of Wales. My presence on the trip was as a guide as I know the location of the plant on one of our sites, Brandon Mountain. A quick flick through the herbarium sheets showed a large number of specimens from Black Head, Co Clare and Brandon Mountain, Co. Kerry. As Colin had already collected from the Black Head plants and I knew the location of the Brandon plants we needed other locations. This was provided in the form of specimens from the Galtee Mountains in Tipperary collected by the great Irish botanist Maura Scannell. A few specimens from various locations around Macgillicuddy's Reeks gave us a third site and completed our itinerary.

Saxifraga rosacea,
specimen from Black Head, Co Clare,
1892, in DBN

With the sites selected I left the others to collect material from the herbarium and went to survey the glasshouses around the gardens. The first weed of interest was shown to me by the horticultural staff. The fern ally Psilotum nudum occurs frequently as a weed in pots in the tropical propagation house. This species, the only representative of the division Psilophyta, is the most primitive extant vascular plant. Psilotum has been noted as a weed on previous occasions but I had not expected to encounter it in such a situation.

Psilotum nudum, National Botanic Gardens of Ireland,
April 2013

Across the yard in a run-down polytunnel a collection of Irish natives had gone wild. The most abundant colonist of other species' pots was Cornish Moneywort, Sibthorpia europaea. This species, a rare native inhabitant of damp places in the extreme south and west of the British Isles, is shown below invading a pot of seemingly dead pot of Seriphidium maritimum.  

Sibthorpia europaea, National Botanic Gardens of Ireland,
April 2013

Oxalis corniculata and O. exilis were, of course, abundant much to the consternation of the gardeners. The cracks in the floor of one of the glasshouses provided a nice example of the two species growing in proximity.

Oxalis corniculata (purple)
and O. exilis (green)
National Botanic Gardens of Ireland,
April 2013

Inside and outside the purple form of Annual Meadow Grass, Poa annua f. purpurea grew in abundance. This form was described in a 2003 paper by M. L. Grant from the RHS gardens at Wisely. This is an interesting form in that, as Grant notes, it blends in very well when growing on bare soil and therefore possess a selective advantage over the more conspicuous green form in the weeded garden environment.      

Poa annua f. purpurea, National Botanic Gardens of Ireland,
April 2013

Poa annua f. purpurea, National Botanic Gardens of Ireland,
April 2013

Leaving the propagation area I conducted a mostly fruitless search of the very hygienic ornamental glasshouses. Around a water feature in the Rhododendron House I found mats of the amusingly named Mind-your-own-business, Soleirolia soleirolii. Its tiny flowers straining the ability of my lens.

Soleirolia soleirolii, National Botanic Gardens of Ireland,
April 2013

Leaving the city we headed across the centre of Ireland to Cashel where we stayed overnight in preparation for our trip up the Galtee Mountains. The morning saw us ascend a forestry track onto the sunny moors. Reaching the crags around Lough Borheen where Scannell's 1980's  for S. rosacea collection was made we began searching  the icy gulleys. Our search was not immediately rewarded but some pleasant upland species were observed. Firstly, Fir Clubmoss, Huperzia selago was found growing in rock cracks. The small upland moss Hedwigia stellata was seen growing on boulders its white-tipped leaves standing out from the pinkish red sandstone. 

Huperzia selago, near Lough Borheen, Co. Tipperary,
R 9037 2448, April 2013

Hedwigia stellata, near Lough Borheen, Co. Tipperary, 
R 9017 2482, April 2013, VCH7

After a few fruitless hours we discovered a small population of S. rosacea half covered by ice in a gulley on the slightly lower crags near the lough. As Natasha collected samples into silica gel for analysis back home Tracey and I found a number of extra plants some way further down the gulley. 

Saxifraga rosacea, near Lough Borheen, Co. Tipperary, 
R 8994 2450, April 2013, VCH7

Continuing south the following day we ascended Mount Brandon on the Dingle Peninsular. The weather had turned windy and some flurries of snow greeted us as we reached the high ground. S. rosacea was found after a short search growing in runnels and, later, on rocks in a small stream. The weather closed in preventing us from concluding a search for Alpine Lady's-mantle, Alchemilla alpina. We did however find a large clump of Thrift, Armeria maritima, a species that is best know in its sea cliff habitat but also occurs on high mountain rocks and on heavy metal spoil heaps.  

Natasha De Vere, Colin Kelleher & Tracey Hamston, Brandon Mountain 

Saxifraga rosacea, Brandon Mountain, Co. Kerry, 
Q 4657 1273, April 2013

Armeria maritima, Brandon Mountain, Co. Kerry, 
Q 4657 1273, April 2013

The final day of our trip began with some botanical tourism around Killarney National Park. Our first stop was at a site where I had last seen the elusive Killarney Fern, Trichomanes speciosum in 2003. After a somewhat treacherous river crossing we found a large colony at the base of a small cliff.

Trichomanes speciosum, Near Killarney,
April 2013

Trichomanes speciosum, Near Killarney,
April 2013

A second stop was in a roadside lay-by serendipitously beside a couple of Strawberry Trees, Arbutus unendo. The boulders around were covered in lush growths of both filmy ferns (Hymenophyllum tunbrigense, H. wilsonii) as well as St. Patrick's cabbage, Saifraga spathularis.  

Arbutus unendo,
Killarney National Park, April 2013

Hymenophyllum wilsonii Saifraga spathularis,
Killarney National Park, April 2013

The final search for S. rosacea proved to be fruitless somewhat ruining our otherwise perfect record (of two). Our trip complete we retreated to Cork in the pouring rain.

Perry, Jesse P., and Lytton J. Musselman. "Psilotum nudum new to North Carolina." American Fern Journal 84.3 (1994): 102-104.