A tuberous perennial herb of short turf on calcareous soils overlying chalk or oolitic limestone, particularly on the small terracettes of steep slopes. It also grows on quarry floors and on old lime kiln spoil heaps. Lowland.
By 1930 this species had been lost from many sites, especially in East Anglia, through ploughing and increased grazing. Losses have continued, mostly due to a lack of grazing and consequent scrub encroachment, but have been partly offset by its ability to colonise new sites such as quarries.
Eurasian Temperate element, with a continental distribution in W. Europe.
Light (Ellenberg): 8
Moisture (Ellenberg): 5
Reaction (Ellenberg): 8
Nitrogen (Ellenberg): 2
Salt Tolerance (Ellenberg): 0
January Mean Temperature (Celsius): 3.6
July Mean Temperature (Celsius): 16.2
Annual Precipitation (mm): 770
Height (cm): 15
Perennation - primary
Life Form - primary
Clonality - primary
Count of 10km squares in Great Britain: 104
Count of 10km squares in Ireland: 0
Count of 10km squares in the Channel Isles: 0
Atlas Change Index: -0.93
Scarce Atlas Account
Herminium monorchis (L.) R.Br.
One of the smallest of our native orchids, H. monorchis grows in short turf in calcareous grassland. It grows particularly well on narrow terracettes formed on steep slopes by soil creep. It also favours the floors of old quarries, where infertile soils and compaction restrict the growth of other taller-growing species. It is confined to the lowlands.
It multiplies vegetatively by producing tubers on the end of slender root-like rhizomes, forming small colonies around a `mother' plant, but separated from it by as much as 10 cm. Large colonies can arise by this means over a number of favourable years.
Flowering fluctuates greatly from year to year. In dry years, populations may cease to flower completely but individuals survive as small rosettes of leaves which are easily over-looked. The flower-spike is produced in late June or July and consists of many yellowish-green or green, sweetly scented flowers, closely packed together. Capsules are set and seeds dispersed by August. Leaves die down in late September and do not appear again until late May the following year.
H. monorchis has been lost from many of its former downland localities, especially in East Anglia, but it does have the ability to colonise new sites such as quarry floors.
H. monorchis is a member of the Northern Eurasian group of British orchids and is widely distributed throughout the northern parts of these two continents. Elsewhere in Europe it is not restricted to calcareous soils and it often grows in much damper places than those in which it is found in Britain.
T. C. E. Wells
Atlas text references
1986. Atlas of north European vascular plants north of the Tropic of Cancer. 3 vols.
1965. Vergleichende Chorologie der zentraleuropäischen Flora. Volume 1. 2 vols.
1991. The orchids of Suffolk.
1994. Scarce plants in Britain.
1998. Flowering dynamics of Orchis morio L. and Herminium monorchis (L.) R. Br. at two sites in eastern England. Botanical Journal of the Linnean Society. 126:39-48.