Bog Twayblade

Fen orchid flowers throughout the months of June and July, and the fen variety is believed to prefer areas where peat cutting is taking place. The orchid colonises the bare fen surface as an 'early successional' species, taking advantage of a new habitat. Where it occurs on its Broadland site, it can appear quite numerous, and 242 plants were found in 1996.

Fen orchid is listed in the UK Biodiversity Action Plans (UK BAP), and is included in English Nature's Species Recovery Programme (SRP). All the populations of the plant are within National Nature Reserves (NNRs), which are also protected as Sites of Special Scientific Interest (SSSIs). The Welsh sites are the subjects of a major management project for the species, co-ordinated by the Countryside Council for Wales (CCW). The Norfolk Wildlife Trust, the lead partner for this species in England, have produced a management plan to conserve the orchid. This includes the possibility of re-introducing it on to suitable sites within its known former range.

This rare orchid appears initially as a green scaly-looking bulb amongst the wet moss of a fen or a dune slack. There are two closely related varieties of this plant, although some authorities seem to be questioning this. They both usually have two leaves on opposite sides of the stem, emerging from the base. The East Anglian subspecies has leaves that are spear-shaped, pointed at the ends and rather shiny and greasy-looking. The Welsh variety (var. ovata) has blunter, more elliptical leaves and is a shorter plant generally. The flowers are grouped rather loosely at the top of the stem and are a yellow-green in colour. The flower 'spike' makes up the top 2-10 cm of the height of the plant. The Welsh variety usually has a shorter flower spike. The specific name loeselii commemorates Johann Loesel, a seventeenth century Prussian botanist.

The two sub-species require different habitats, the East Anglian variety favouring mossy calcareous fens, while the Welsh variety prefers wet dune slacks.

This species was once known from more than 30 separate sites but, today, is thought to survive at just four sites. Two of these are in the Norfolk Broads in East Anglia, whilst the variety ovata is found on two dune systems in South Wales and, until fairly recently, was also found in North Devon. This orchid is also found across much of central Europe where it is rare but described as 'locally common'.

Listed under Annexes II(b) and IV(b) of the EC Habitats Directive, Schedule 4 of the Conservation (Natural Habitats, etc.) Regulations 1994 and Schedule 8 of the Wildlife and Countryside Act, 1981.

The chief threats to this species are loss of habitat through drainage and pollution, and the abstraction of groundwater for irrigation of crops. The orchid may also have declined through a cessation of peat digging, which provided suitable conditions for new colonies to form.

Foodplant / mycorrhiza
live root of Liparis loeselii is mycorrhizal with live mycelium of Fungi ss.

At first sight, the fen orchid is not what one would call a beautiful orchid. It is short, has a greasy look and its small blossoms are grouped loosely at the top of the stalk. However, the fen orchid is rare and therefore protected. It can be numerous in some places in the Netherlands, such as the dunes on the Wadden Islands and in the Grevelingen region. Otherwise, it is only found sporadically in fens. It grows mostly in damp young, primary dune slacks, just behind the beach ridge. As soon as the soil ages and there is less dynamics, this orchid disappears.

Liparis loeselii is such a small orchid that it can be easily overlooked; it may have a wider distribution than has been reported. Rain-assisted self-pollination in this species was described by P. M. Catling (1980).

Plants 6–26 cm. Pseudobulbs ovoid, 10 × 5 mm, sheathed by bracts and persistent leaf bases, previous year’s pseudobulb usually present, connected by short rhizome. Stems pale green or yellowish green, angled, sometimes obscurely winged or fluted distally. Leaves 2; blade conduplicate, green, glossy, oblong-elliptic to elliptic-lanceolate, keeled abaxially, 3.7–18 × 1–4 cm, succulent, apex obtuse to subacute. Inflorescences 2–10 cm; floral bracts subulate, minute, 2 × 1 mm, apex acute; pedicels slender, 3–5 mm. Flowers 2–15, green or yellowish green to yellowish white or greenish white; dorsal sepal oblong-lanceolate to narrowly lanceolate, 4.5–6 × 1–2 mm, apex obtuse to acute; lateral sepals oblong-lanceolate to narrowly lanceolate, 4.5–5.5 × 1–2.2 mm, apex obtuse to acute; petals pendent, slightly curved, tubular, filiform, 4.5–5.5 × 0.5–1 mm, margins strongly revolute; lip translucent to opaque, green or yellowish green to yellowish white, obovate to oblong to suborbiculate, 4–5.5 × 2.2–3.5 mm, base narrowly cuneate, slightly auriculate, margins crenulate-wavy, apex subtruncate to obtuse, mucronate; disc with central elongate thickening; column short, stout, 2–3 × 0.5–1 mm, winged apically; anthers yellow; pollinia yellow. Capsules: pedicel 3–7 mm; body obovate to ellipsoid, 9–13 × 3–6 mm, veins often slightly winged. 2n = 32, 26.

B.C., Man., N.B., N.W.T., N.S., Ont., P.E.I., Que., Sask.; Ala., Ark., Conn., Del., Ill., Ind., Iowa, Kans., Ky., Maine, Md., Mass., Mich., Minn., Miss., Mo., Mont., Nebr., N.H., N.J., N.Y., N.C., Ohio, Pa., R.I., Tenn., Vt., Va., Wash., W.Va., Wis.; w, c Europe.

Flowering May--Aug.

Cool, moist ravines, bogs, or fens, wet peaty or sandy meadows, and exposed sand along edges of lakes, often colonizing previously open and disturbed habitats during early and middle stages of reforestation; 100--1100m.

Ophrys loeselii Linnaeus, Sp. Pl. 2: 947. 1753; Leptorchis loeselii (Linnaeus) MacMillan; Liparis correana (Barton) Sprengel; Malaxis correana W. Barton; M. longifolia W. Barton

Liparis loeselii, the fen orchid, yellow widelip orchid, or bog twayblade, is a species of orchid. It is native to Europe, northern Asia, the eastern United States, and eastern Canada. It grows in fens, bogs and dune slacks. It has yellow flowers and glossy yellow-green leaves.

Subspecies Liparis loeselii subsp. loeselii - Europe, Russia, Kazakhstan, Canada, United States Liparis loeselii subsp. orientalis Efimov - Altay region of Russia Liparis loeselii subsp. sachalinensis (Nakai) Efimov - Sakhalin Island in Russia