Orchids will have them on their knees

Another Life: The first and only orchid I picked and brought home, from a grassy bank in Connemara, was the elegant, ivory spire of the greater butterfly orchid, then an exotic novelty for me.

As night fell, this single blossom, seeking pollination by long-tongued moths, filled the room with such intense and sweet fragrance that the astonishment has lasted 40 years.

How unfortunate then, that the west's first orchid of the year, the early purple, magairlín, smells of cat's piss.

"Even one solitary flower," writes Brendan Sayers, "kept for a couple of hours in a tightly sealed box and then removed, emits the same powerful, unmistakable scent." I can't wait to get over to the rocky ridge across the lake, now alight with every hue of "early purple", to take a sniff for myself.

Sayers is the authority on orchids at the National Botanic Gardens, Glasnevin, and his observation is a lively aside in one of the most beautiful books in the history of Irish botany. Ireland's Wild Orchids presents 35 watercolour paintings by Susan Sex, a botanical artist now being showered with medals by the Royal Horticultural Society. Her work has precious detail and exactitude, in the high modern tradition of Wendy Walsh and Raymond Piper, but also a lively romanticism recalling the 19th-century heyday of plant portraiture.

The watercolours themselves have been given to the archives of Glasnevin. Even with substantial patronage, this lavishly-bound book costs 245 (and another €20 for a slip-case), but some 500 of the 700 copies are already spoken for. At some later stage, I hope, there will be a more affordable edition, for both the botany and the beauty of the book, the first devoted exclusively to Irish orchids, belong to the national heritage.

It took six years to complete, and much trudging over hills, fields, rocks, quarries, dunes and marshes to track down all the species. A third of them are now rare and many are notorious for appearing in hundreds in some years and meagre dozens in others. The dust-fine seed of orchids, carried on the wind, must strike up the right relationship with a soil fungus, in precisely the right habitat, to survive at all, and years can then pass before the plant reaches maturity.

While some tropical orchids are threatened by over-collection, it is the loss of habitat - mainly through drainage and fertilising - that has sent many Irish species into decline. Finding presentable plants of one small white orchid, on overgrazed hills, took three frustrating trips.

Road-widening often shears away the banks where orchids flourished, or tops the new verges with rich soil that smothers the plants with grass.

Brendan Sayers makes a case for leaving poor, gravelly slopes as ideal roadside nurseries. He also has a kind word for golf links on orchid-rich dunes, so long as they are managed sympathetically. At Cruit Island, Co Donegal, for example, a links on coastal machair carries "huge populations" of a deep-pink spotted orchid shared with the Hebrides, and Portmarnock Golf Club in Co Dublin "has been a treasure trove of orchids for many years".

County Dublin figures quite buoyantly in Sayers's notes. Who'd have thought, for example, that the tall and stately marsh helleborine grows so densely in the wet dune slacks at North Bull Island in Dublin Bay that it is "almost impossible" not to tread on a plant? Or that about 10,000 of the raspberry-pink pyramidal orchid were in blossom on the island last summer - a display that outdid even the celebrated spectacle at Fanore, on the coast of the Burren? Like 1995, 2003 was an exceptional year for orchids - helped, perhaps, by the dull, wet weather of 2002 which let the plants store up some energy.

A few weeks ago, Sayers made his annual trip to a three-acre meadow at the Burrows in Donabate, Co Dublin, a few hundred metres from the sea. Here, among the buttercups, were more than 500 flowering plants of the green-winged orchid - the east coast's first orchid of the season.

In Britain, this species, flowering in old pastures in shades from pale pink to deep purple, has become so rare that Kew Gardens have had to grow it for reintroduction in nature reserves. In Ireland's first Red Data Book in 1988 it was reported at only a handful of sites and needed immediate protection. Today, it has more than 50 sites and protection has been relaxed.

Ireland's comparative profusion of orchids, and the challenge of their almost capricious variation in height, habitat and colour, bring botanists to Ireland from all over Europe. Ireland's Wild Orchids should, in every sense, have them on their knees.

The book can be ordered from Susan Sex-Wild Orchids, The Retreat, St Anne's Square, Portmarnock, Co Dublin, with the cheque made out to the same title.