Herminium L.

Specics of Herminium typically grow in calcareous to neutral soils (Davies et al. 1988; Delforge 1995). In the British Isles, for example, H. monorchis R.Br. is principally found on the chalk downland of Kent, Sussex, Surrey, Hampshire, Wiltshire, and the Chilterns in the south of England and on the oolitic limestone of Somerset and Gloucestershire in the west of the country (Summerhayes 1951; Lang 1989). lt normally grows in short grass such as among the short turf of the chalk downs, old pastures, old quarries, and on the spoil-heaps of ancient chalk-pits (Summerhayes 1951; Lang 1989; Sanford 1991; Wells et al. 1998). in the Cotswolds, H. monorchis is particularly abundant on bare quarry floors, and Lang (1989) reported it persisting in an old chalk pit in Kent more than 100 years after it was first recorded there in 1871. Wells et al. studied a population of H. monorchis between 1966 and 1995 that grows in species-rich chalk grassland (CG5 in the National Vegetation Classification, Rodwell 1993) that had developed over old quarry spoil (Wells 1981; Wells et al. 1998). The site, at Tottenhoe Knolls in Bedfordshire, is maintained in a short and open condition by scrub removal, winter sheep grazing, and high levels of rabbit herbivory.
Since it invariably grows in open habitats such as those at Tottenhoe Knolls, H. monorchis is thought to be intolerant of shade in Britain but is able to withstand some levels of drought as many of its sites in England can become dry in the summer (Summerhayes 1951). Outside the United Kingdom, H. monorchis often grows in both wetter and more shaded habitats, as do other members of the genus. Herminium species are recorded from coastal sand-dune slacks, marshes, and damp meadows (Davies et al. 1988; Delforge 1995), shrubby vegetation (Dassanayake 1981) and forests and marshy ground (Dassanayake 1981) as well as from fields, roadsides, and grasslands elsewhere in Asia (Ohwi 1965; Walker 1976). Herminum can grow at a range of elevations from sea level in the northern parts of its range as in Britain (Summerhayes 1951) up to 2400 m in moutainous areas in Europe (Delforge 1995), and at even higher elevations in the Himalayas (Hara et al. 1978). Indeed, in his Flora of British India, Hooker (1894) noted that 'the Indian Herminia are all mountain or alpine, and attain the greatest elevation of any orchids'.
Across its geographic range, Herminium flowers between May and August, the exact period depending on the elevation of the population (Dassanyake 1981; Davies et al. 1988; Delforge 1995). Peak flowering of H. monorchis in England, for example, is normally in the last two weeks of June and the first two weeks of July (Summerhayes 1986; Lang 1989; Sanford 1991; Wells 1998) . Flowering of this species is preceded by leaf expansion, the leaves emerging from below ground in either May or June depending on whether there has been sufficient rainfall to promote early growth (Wells et al. 1998). In normal years, the leaves are green until mid-September, but if there is a summer drought, they remain small and turn yellow so that they are unable to photosynthesize by midsummer. Adverse weather conditions such as drought or high summer temperatures are thought to influence patterns of flowering in H. monorchis at least. Flowering of this species is often described as being highly variable, with marked fluctuations being seen in the number of flowering stems produced by populations from year to year (Summerhayes 1951; Lang 1989; Delforge 1995). In the long-term study population of H. monorchis at Tottenhoe Knolls in England, for example, the average proportion of flowering plants was 16.9%, but this varied from 0 in 1977 and 1991 to 36% in 1972 (Wells et al. 1998). By causing premature senescence of the leaves, unusually warm and dry seasons reduce the amount of carbohydrates that can be produced and stored by a plant with the result that the subsequently smaller tubers are unable to initiate inflorescence formation the following year (Wells 1998). Herminium monorchis seems to be particularly sensitive to climatic variations during its period of active growth (June to October), but its tubers enable it to survive in a dormant state during unfavourable conditions. Wells et al. (1998) noted that the population at Tottenhoe was able to maintain itself solely by vegetative means because from 1990-1995 all inflorescences (77 in that period) were grazed by rabbits, and there had been no fresh seed input to the site fo r five years.
Fruit-set in H. monorchis is normally high, for example 88.7% in one population in Sweden (Nilsson 1979), and has been attributed by several authors to a high degree of self-pollination even in the absence of pollinators (e.g. Summerhayes 1951; Lang 1989). However, Nilsson (1979) demonstrated that insects were necessary for pollen transport in the species because no fruit was set if inflorescences were experimentally isolated throughout anthesis as pollinia did not come into contact with the stigma without the intervention of a pollen vector. Seedlings are rarely observed in the field (Rasmussen 1995), which has led to the suggestion that propagation of the species is principally by vegetative means (Delforge 1995). Vegetative reproduction in Herminium is efficient because two or three additional new tubers are normally produced on stolons up to 20 cm long (Davies et al. 1988; Lang 1989). Given the consistent large input of seeds, it is probable that both vegetative and sexual reproduction contribute to the propagation of the species and formation of large colonies in the field of several thousand plants at some sites (Delforge 1995). Rasmussen (1995) observed low germination rates of seeds with Rhizoctonia fungi (3- 13%) on nutrient media, but asymbiotically cultured protocorms grew well, and flowering plants could be obtained within two years after sowing. Earlier observations also indicated that H. monorchis requires a period of several years before reaching flowering size under natural conditions and that the tip of the tuber is mycorrhizal, whereas fungi are absent from other underground parts of the plant (Fuchs and Ziegenspeck 1925, cited in Rasmussen 1995).
Despite its high seed productivity and efficient means of vegetative propagation, which can make it abundant at favourable sites, H. monorchis has a localized distribution in the UK and in other temperate and boreal areas. Summerhayes (1951) suggested that the species, which is at the edge of its range in Britain, is restricted by climatic variables. It avoids the western parts of the British Isles and continental Europe that have a damp oceanic climate. In recent years it has declined in numbers and is now uncommon (Davies et al. 1988), even in areas where it was previously common. For example, in Suffolk in south-east England it has been extinct for over 170 years. Sanford (1991) attributed its disappearance to changing agricultural practices in the region, whereby many open fields were ploughed up after 1800 to grow arable crops, and sheep grazing, which kept the grass short, was moved to other areas. He compared the decline of H. monorchis to that of Ophrys fuciflora in England and speculated that climatic changes could have been an important factor in the reduction of the occurrence of the species in England. It is also rare in other parts of its range such as Japan where it occurs in Hokkaido (Ohwi 1965). Other Herminium species reported as rare include H. forrestii Schltr. in China (Cribb 1994) and H. longicure Benth. & Hook.f in Japan (Ohwi 1965). Pradhan (IUCN Orchid Specialist Group 1996) listed the Indian endemic species, H. kalimpongensis U. C. Pradhan, as the most threatened orchid species of the country because it has not been recorded for a long time. Other members of the genus are common in parts of the range of the genus: H. lanceum (Thunb. ex Sw.) Vuijk in south-east Asia, Pakistan to south-west China (Polunin and Stainton 1984) and H. monorchis and H. ophioglossoides Schltr. in Yunnan in China (Cribb 1994). (RN).

Small, terrestrial, glabrous herbs with oblong, undivided tubers. Leaves solitary or few, green. lnflorescence erect, laxly to densely many-flowered; bracts small, lanceolate. Flowers small, often spidery, yellow or green. Sepals subequal, dorsal free or connivent into a hood, the laterals spreading. Petals smaller than the sepals, often connivent with dorsal sepal to form a hood over the column. Labellum continuous with the column base, spreading or pendulous, entire, bilobed or trilobed, flat, concave or obscurely saccate at the base, ecallose. Column short; anther bilocular, adnate to the face of the column; loculi parallel; pollinia two, with short caudicles; viscidia two, small to large; lateral appendages prominent, sometimes shortly stalked; stigma bilobed, convex, clavate; rostellum short. Ovary sessile. (PC).

A genus of about 30 species widely distributed in Europe, North Africa, the Middle East,and Asia to Japan, China, including Taiwan, and south to the Himalayas from Pakistan eastward, south-east Asia, the Philippines, and Indonesia. (PC).