NATURE Insectivorous wildflowers in Mayo


Country Sights and Sounds
John Shelley

I walked with Ian the Botanist, from whose mouth spill the Latin names of native plants with disconcerting fluency. Together we walked the shore of Lough Mask to find Drosera rotundifolia, the humble round-leaved sundew, and discovered its two cousins longifolia (the great sundew) and intermedia (oblong-leaved) living in close proximity, at the edge of nutrient-poor bog pools, where the only nourishment to be found is flying overhead.
The sundew eats insects, attracting them by means of glistening beadlets of glue attached to hairs around the perimeter of its leaves. When a hungry or inquisitive fly lands in anticipation of a meal it finds its feet held fast, and when it struggles for freedom its predicament becomes only worse as more and more hairs reach in to tether the hapless creature and hold it fast throughout its many struggles. It backs off from the glue and seeks a firm foothold in the middle of the leaf, where proteolytic enzymes immediately set about digesting the catch.
I imagine the sundew endowed with eyes and thinking ability. The collective army present on the bog might conceivably trap an unwary passer-by and dissolve him to the bone, leaving nothing more than a skeleton and wellington boots to tell the gruesome tale. It has even been reported that if small pieces of steak are placed alongside sundews, that  they reach with their leaves in order to feed. So do watch out when working on the bog. The sundews are watching you – and they move so silently in their sphagnum bed you wouldn’t know just when they might pounce!
Actually, these little plants are very attractive. The leaves form a pale green rosette, edged with red and sparkling with sticky sap in even the driest weather. In midsummer a frail stem arises from the centre and from this, tiny white flowers appear. These open on sunny days and sometimes not at all; whether they do or do not makes little difference, for these flowers are self-pollinated, which acts as a guarantee for the preservation of a species given to such wet and windy conditions as prevail on Irish peatland.
We have other insectivorous plants with us, too. On slightly drier ground we found scores of common butterwort (Pinguicula vulgaris, says Ian), their succulent leaves arranged like bright green stars against the dark soil, and on an exposed bank a few solitary specimens of the rather charming and delicate Pinguicula lusitanica, known by the partly educated layman as the pale butterwort. See how saying things in Latin catches on!
Nor are we finished there. In shallow water we found Ulticularia vulgaris – okay, the greater bladderwort. This interesting plant has no roots. Indeed, it has no need of them, as it floats just under the surface of the water. It grows long stems which support a mass of spindly leaves. These, in turn, carry a most ingenious and bizarre mechanism that is used in the trapping of tiny invertebrates and even fish fry.
Shaped like tiny bladders, these traps have a hinged and spring-loaded front door surrounded by tiny, touch-sensitive hairs. When some small aquatic creature brushes against the hairs the trapdoor is triggered. It opens inwards in only a few thousandths of a second, creating an inrush of water that carries the prey item with it. Once inside the bladder the door closes once more and there can be no escape. The trapped animal might kick and wriggle for all it is worth but is slowly digested.
The bladderwort we found had been left high and dry by dropping water levels, and for the most part all we saw of them were the rusty brown flowering stems, each of which was adorned with a small number of striking yellow flowers.
Aside from this host of carnivorous plants we made many other interesting discoveries, not the least of which was the Irish St John’s wort (Hypericum canadense). First discovered in Mayo in 1954, this is a North American species that was somehow introduced. Some say it was carried on the feet of migrating wildfowl, but nobody really knows.
When we searched for it five years ago it refused to be found. Now it appears in rich flushes with such abundance we can hardly consider it the rarity it truly is.
A day spent walking with Ian was a revelation, and now I have a new interest to pursue. Who knows what waits to be discovered?