Galium uliginosum L., Fen Bedstraw

Account Summary

Growth form and preferred habitats

G. uliginosum, variously referred to as Fen-, Swamp- or Bog-Bedstraw, a perennial which develops 4-angled, decumbent or ascending aerial stems and branches from a slender creeping rootstock, is like a weaker, even more slender, scrambling form of G. palustre (), from which it can be distinguished by the backwardly directed hairs (ie recurved, pointing towards the leaf base), on the margins of the narrower, stiffer, one-veined leaves that have a bristle-like, though mucronate leaf tip (ie an abrupt bristle-like tip) (Clapham et al. 1987; An Irish Flora 1996). Despite their slenderness, the stems, 10-60 cm long, are loosely covered with minute, recurved prickles or papillae that feel rough or scabrid to the touch (Stace 1997). These papillae presumably assist the stems to scramble over neighbouring plants in a manner similar to the very much more common and familiar G. aparine (Cleavers).

Leaves are borne in whorls of six to eight and are narrowly oblanceolate, acute, about 5-10(-15) mm long, with a prominent midrib, and, as mentioned above, their margins bearing small, recurved prickle-like hairs (Hutchinson 1972; Clapham et al. 1987; Sell & Murrell 2006).

G. palustre (Marsh-bedstraw) and G. uliginosum occur in generally similar wetland situations and they can occur together, although Fen Bedstraw is characteristic of and ± confined to nutrient-poor, base-rich or calcareous sites that are permanently wet at the surface through ground-water seepage, but that have little or no standing water in the summer (Hancock 1942). It thus occupies rather drier ground than does G. palustre. It appears in lowland marshy grassland or tall herb fen, including lime-rich flushes with trickling groundwater on wet to moist moorland grasslands and, locally, in wet marshes and fen ground around a few of the peaty lough shores in Co Fermanagh (H33).

It also occurs more rarely in lime-rich flushed ground in more upland moor- and bog-land peaty pastures, even when these form part of tussocky acid bogland.

In B & I, G. uliginosum reaches its highest altitude at 750 m at Cross Fell in Cumberland (VC 70) (W.R. Meek, in: Preston et al. 2002).

Life cycle

Other than straightforward observation there appears to be little scientific knowledge or information available on the life-cycle of G. uliginosum. From its appearance, it probably is a fairly short-lived, hardy perennial. It possesses a slender creeping rootstock and weak, scrambling or sprawling stems bearing semi-evergreen linear leaves which require the support of surrounding taller plants to lift their canopy towards the light.

Although capable of both vegetative and seed reproduction, the latter is very probably the main method of the species' increase and survival. Many of the pastures and fens it occupies are nutritionally poor, regularly grazed and some are seasonally flooded. The species is, therefore, adapted to nutrient stress and moderate disturbance and is much more likely to be a stress tolerator than a vigorous competitor (Grime et al. 1988, 2007).

Flowering reproduction

Flowering takes place from June to August, and G. uliginosum flowers comparatively sparsely compared to G. palustre and its close relatives (ie G. elongatum C. Presl. and G. debile Desv. non Hoffmans. & Link), the blossom being borne in numerous small cymose panicles in the axils of upper stem leaves, rather than in the large terminal inflorescence of G. palustre.

The flowers are larger than those of G. palustre, although still only 2 mm across and, once again, the calyx is absent. The corolla is white, 4-lobed and has a very short tube. The spreading corolla lobes are triangular. The four stamens alternate with the corolla lobes and the style is attached to the inferior, 2-lobed ovary, which bears two rounded stigmas. The flowers are sweetly coumarin scented and attract small insects as pollinators. The fruit is 2-lobed, 1 mm in diameter, finely granular all over its surface and it is ultimately brown in colour (Hutchinson 1972; Clapham et al. 1987).

Seed dispersal is most probably effected by floatation in water, but transport in mud adhering to passing animals, including waterfowl, is also possibly significant. Excreta of Red and Fallow Deer in Sweden contained viable seed of G. uliginosum, so internal transport by other animals is feasible (Ridley 1930, p. 372). Grime et al. (1988, 2007, p. 294) report that G. uliginosum is less able than G. palustre to spread by re-rooting of plant fragments, but as is regularly the case with rarer, declining plants, there does not appear to be any published, readily available data on such matters as mean seed production per plant, or estimates (or even observations) of seed dispersal distances the species is capable of achieving, seed longevity, colonising ability, or rate of population turnover anywhere. Clearly further study is required.

Fermanagh occurrence

G. uliginosum is a plant of limited habitat range and in Fermanagh it is confined to base-rich, marshy ground, as in flushes on moorland and marshy fens around a few lough shores. There are records in just five Fermanagh tetrads, widely scattered around the S & E boundary of the VC.

The details of the other four Fermanagh stations are: Drumacritten Lough, 1988, NI Lakes Survey Team; flush on moor S of Slieve Beagh, 13 August 1995, RHN (private voucher); flush at Tonymore Td, Slieve Rushen, 26 August 1995, RHN (private voucher); in fields at Derryvore Td, near Crom, July 2009, S.A. Wolfe-Murphy.

Irish occurrence

Fen Bedstraw is quite a scarce, local and possibly declining perennial herb in most of Ireland beyond the Central Plain where it is more frequently met. Despite this, it has been recorded at least once in 33 of the 40 Irish VCs (Cen Cat Fl Ir 2). It is very rare in the north of the island, being confined to a few sites in Cos Fermanagh (H33), Armagh (H37) and Down (H38). While the CEDaR Centre Vascular Plant Database contains records from four sites in Fermanagh, three in Co Armagh and nine in Co Down, only two of the Fermanagh records are supported by voucher specimens. All of the other records must be approached with caution until they are equally validated.

This mild rash of more recent records for the three northern VCs mentioned is not considered to represent a genuine increase in this species occurrence: it merely indicates that G. uliginosum had been easily overlooked until the advent of a systematic and prolonged botanical survey, ie the BSBI Atlas 2000 project.

Elsewhere in Ireland, G. uliginosum is found mainly, but not exclusively, in flushed ground around limestone lakes in 'the central belt' of Ireland, from North Galway and South Clare eastwards. It is absent from the more acidic terrain lying to the south of this belt and from most of the north of the island. Even within N Ireland, almost all the reported sites where G. uliginosum has been reported lie on or close to the southern margins of the three county boundaries (Webb et al. 1996; Preston et al. 2002).

While it still appears to be scarce throughout Ireland, there is a good chance that G. uliginosum remains under-recorded, at least to some extent.

British occurrence

This species has probably been over-recorded in the past in some areas of Britain and Ireland, being confused with forms of G. palustre s.l.

In particular, all records from NW Scotland are considered doubtful and have been removed from BSBI Atlas maps. Some other early records may also be errors for G. palustre. Even allowing for this, analysis of the BSBI Database reveals a widespread decline in this species has taken place across B & I since 1950, through the loss or damage of its decidedly narrow range of suitable habitats (Rich & Woodruff 1990).

G. uliginosum remains widely scattered and locally frequent across Britain as far north as Inverness, although it appears absent (or unrecorded) from much of N & W Scotland, including the northern and western isles. It is also absent from the Channel Isles and is rare in parts of SE England (W.R. Meek, in: Preston et al. 2002).

The confusion with G. palustre appears to have worked in the opposite direction in Northern Ireland, where G. uliginosum was previously considered absent. There has been a minor rash of 16 finds of the latter reported from 1980 onwards in Co Fermanagh, Co Armagh (H37) and Co Down (H38).

European and world occurrence

It is widespread across most of Europe from Portugal and N Spain, N Italy and Greece as far northwards to around 70^oN in Scandinavia and extends eastwards through W & C Asia to reach E Asia. It is, however, almost entirely absent from around the shores of the Mediterranean, except in N Spain and S France. It is present in Morocco. It is reportedly naturalised on N Island, New Zealand and in Greenland (where it is a casual) and the Crozet Islands (Hultén & Fries 1986, Map 1527; Clapham et al. 1987; Sell & Murrell 2006).

Names

The Latin specific epithet 'uliginosum' translates as 'of marshes'.

Current conservation action

All wild plants are given some measure of protection in Northern Ireland under the Wildlife (NI) Order, 1985. Fifty-six species, listed in Schedule 8, parts 1 and 2, are given special protection on account of their rarity, although Galium uliginosum is not included. However since March 2004 it has been listed as one of 69 Northern Ireland Vascular Plants regarded as Species of Conservation Concern (SOCC).

Threats

Its rarity and limited habitat range, together with drainage and pollution, particularly nutrient-enrichment from agricultural runoff, are the major problems facing this and many other wetland species.

References

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