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Galium odoratum (L.) Scop., Woodruff

Account Summary

Native, frequent. European temperate, also native in C & E Asia and introduced very locally in eastern and western N America.

1882; Stewart, S.A.; Co Fermanagh.

Throughout the year.

Growth form and preferred habitats

A sweetly perfumed small white flower adorns this perennial that has a slender, far-creeping rhizome or rootstock. The dried foliage is fragrant, smelling distinctly and very pleasantly of hay, giving the species the often used English common name 'Sweet Woodruff'. The plant grows up to about 30 cm and flowers during May and June. G. odoratum differs from other Galium species in having somewhat larger, up to 6 mm in diameter, funnel-shaped flowers with the corolla tube only slightly shorter than the four corolla lobes (Garrard & Streeter 1983).

Numerous, erect, 4-angled, glabrous, unbranched aerial stems arise from the creeping, branching rhizome or rootstock. The angles of the stem have a narrow colourless margin and there are colourless hairs below the leaf nodes. The stems bear indistinguishable leaves and leaf-like stipules arranged in distant whorls of six to nine 'leaves' around the stems. The leaf shape is variable, but mainly oblong-lanceolate, mucronate at the apex (ie furnished with a short, abrupt point), margins entire and lamina (leaf blade) narrowing at the base to a short, winged petiole. The leaves on the mid-stem measure 25-45 × 6-15 mm. The leaves are all glabrous (hairless) except for the forwardly directed, marginal prickles, which are sometimes also present on the midrib underneath (Sell & Murrell 2006).

G. odoratum (= Asperula odorata) is very regularly found growing among dead leaves under shading trees in damp deciduous woods and glens over limestone, but also occurs locally on more acidic soils and in grassland. The plant demands shade, and if it becomes exposed to full sun it soon dies (Melderis & Bangerter 1955; Hutchinson 1972). In parts of lowland England at least, Woodruff is regarded as a useful indicator species for ancient or long-established deciduous woodland, especially Beech woods, on substrates varying from near neutral, base-rich soils to moderately acidic brown earths, occurring along with regular associates such as Melica uniflora (Wood Melick), Orchis mascula (Early-purple Orchid), Oxalis acetosella (Wood-sorrel) and Sanicula europaea (Sanicle) (Melderis & Bangerter 1955; Rackham 1980; Sinker et al. 1985; Trueman et al. 1995). The established strategy of G. odoratum is categorised as SC/CSR, meaning it is intermediate between a Stress-tolerant Competitor and a more equally balanced mixture of all three strategies, Competitor-Stress-tolerator and Ruderal (Grime et al. 1988, 2007).

Flowering reproduction

The inflorescence is an aggregation of terminal and lateral three-branched cymes constituting a loose cymbose umbel. The flowers, as usual in the genus, have the calyx reduced to an annular ridge that sits above the inferior ovary. The four stamens alternate with the spreading corolla lobes. The sweet perfume and abundant nectar, readily available at the bottom of the short corolla tube of each flower, attracts flies and bees as pollinators. The corolla soon falls off after the flower is fertilised. The fruit consists of two relatively large (for a Galium species) globular, single-seeded mericarp nutlets, 2-3 mm in diameter, densely covered with fine, white, black tipped, flexible hooked hairs or bristles, rendering them like (or into) mini-burrs when they are ripe and dry (Grieve 1931; Melderis & Bangerter 1955; Hutchinson 1972; Sell & Murrell 2006). The current author (RSF) has not uncovered any information relating to the mean number of flowers per plant, or the levels of seed production the species is capable of achieving under different growing conditions. Clearly more work is required on this topic.

As in the more common and familiar relative, Galium aparine (Cleavers or Goosegrass), the burr-like bristly fruits of G. odoratum, which are larger and have longer hooked spines than those of G. aparine, readily adhere to the fur, feathers or skin of small woodland animals (including birds) and the clothing of humans, and are efficiently transported until they fall off at some distance from the parent plant (Ridley 1930, p. 593). In a similar way, even large portions of the plants may be attached and dragged by means of the rough, marginal prickles of the leaves (Hutchinson 1972).

The seed contained within the mericarp or nutlet fruit is of the transient type with respect to soil seed bank survival, persisting for less than one year (Thompson et al. 1997).

Vegetative reproduction

In addition to spread by seed, growth of the underground rhizome or rootstock over prolonged periods in old or ancient woodland stands, enables clonal spread and local patch formation by the species. Again, it would be interesting to know of the scale of such colonies in the field and their rate of growth and turnover over an extended period.

Fossil history

Unknown; not featured at all in Godwin (1975), as either Galium or Asperula.

Fermanagh occurrence

G. odoratum is frequent to locally abundant in Fermanagh and has been recorded in 108 of the tetrads, 20.5% of those in the VC. It most often inhabits deciduous woods, scrub, damp shaded banks and glens, but it is occasionally found in limestone grassland and rarely in old quarry sites. It can form extensive clonal patches in damp, shaded or half-shaded sites, particularly on the Western Plateau and on hill slopes in the limestone areas of the SW half of the county, but it becomes much more thinly scattered in the more intensively farmed eastern lowlands where woodland and scrub are often reduced to small stands or are completely absent.

British and Irish occurrence

Widely distributed throughout B & I except for the Channel Islands, Outer Hebrides, Orkney and Shetland. It is rather scarce in N Scotland and also in East Anglia and northwards to Hull (Garrard & Streeter 1983; Sell & Murrell 2006). In Scotland, it reaches an altitude of 640 m in Atholl, E Perth (VC 89) (W.R. Meek, in: Preston et al. 2002).

G. odoratum is grown in gardens for its beautifully perfumed flowers and appears as an escaped introduction beyond cultivation, as it does for instance in Jersey in the Channel Isles (Sell & Murrell 2006), and also in the Isle of Man (VC 71) (Allen 1984) and scattered locations across Britain.

In Ireland, although the Cen Cat Fl Ir 2 shows G. odoratum occurring in every VC, it is much more thinly distributed than is the case in Britain (BSBI Atlas 2; New Atlas). In An Irish Flora (1996), the species is described as, "occasional, commoner in the North half", and the New Atlas hectad map confirms this view of its distribution.

European and world occurrence

Belongs to the European temperate element in phytogeographical terms and occurs mainly in temperate parts of N & C Europe, montane woods in Italy and the Balkans becoming more thinly scattered in the Iberian Peninsula and around the W Mediterranean. It is present on Sicily and Corsica, but absent from all other Mediterranean islands, although it is sparsely represented in N Africa, Iran and W Turkey. The species is also rarely present in two rather isolated Asiatic regions, the C Asiatic mountains and E Asia through Mongolia to China and Japan. Ridley (1930, p. 593) observes, "There can be little doubt that it owes its wide distribution to small woodland-haunting animals.".

G. odoratum has also been introduced locally and sparingly into eastern and western N America, probably as a garden escape (Hultén & Fries 1986, Map 1518; Sell & Murrell 2006).

Uses

The cool, fresh perfume of the species is from the coumarin content, which, when it is carefully dried, persists for several years; this made it popular in the past for scenting linen and 'laying in' beds for expectant mothers, similar to the use of Lavender (Grieve 1931; Melderis & Bangerter 1955). Dried bunches of the plant were hung in house and church interiors and strewn on floors to hide unpleasant odours, and it was stuffed into mattresses for the same reason.

G. odoratum also had use in the Middle Ages in herbal medicine, fresh leaves being bruised and applied to cuts and wounds for their healing effect. A strong decoction of the fresh herb was used as a cordial and stomachic, and it was also said to be useful for removing biliary obstructions of the liver (ie affecting bile ducts) (Grieve 1931). It was drunk as a tea for headache, colds and consumption and was used to flavour beverages from herbal tea and fruit juice to wine (Grigson 1955, 1987; Mabey 1972).

G. odoratum has been used in pharmacy to disguise disagreeable odours, especially that of iodoform. The enduring fragrance of Woodruff is also put into potpourri (Grieve 1931). Coumarin not only has a very pleasing smell of itself, it is (or was) used in perfumery to fix other odours (Grieve 1931).

A sprig of G. odoratum steeped in pure apple juice for a week is described by Mabey (1972) as 'ambrosial'!

Names

The genus name 'Galium' is a name in Dioscorides derived from the Greek 'gala', 'milk', that was first given to Galium verum, a herb widely used to curdle milk for cheese making (Johnson & Smith 1946; Gilbert-Carter 1964). The Latin specific epithet 'odoratum' is derived from 'odōro', meaning 'scent sweetly' and thus translates as 'sweet-smelling' or 'fragrant' (Gilbert-Carter 1964).

There are a total of 19 English common names listed by Grigson 1955, 1987). The most widely used common name 'Woodruff' is derived from the Old English 'wuda-rōfe', ie 'wood-' plus a word or plant name implying roving, creeping or spreading (Grigson 1974). An old Northern Ireland common name for the species is 'Hay-plant', the lovely coumarin perfume the dried plant contains also occurring in Anthoxanthum odoratum (Sweet Vernal-grass), which is very much associated with the sweet smell of cut and drying hay (Grigson 1955, 1987; Genders 1971). Likewise, in Somerset and Nottinghamshire, the English common name for G. odoratum is 'New-mown-hay'.

Prior (1879) and Britten & Holland (1886) provide another interesting name, 'Mugwet', originally introduced in Gerard (1633), from the French name 'Muguet'; the name refers to the fragrance of the flowers and is derived from the Old French 'musquet', from the Latin 'muscatus', meaning 'scented with musk', or from the Latin 'musquettus', a diminutive of 'muscus', meaning 'musk', a name applied in French to several flowers. Other names like 'Star-grass' refer to the whorled leaves, while 'Blood Cup' remains a total mystery as far as the current author is concerned.

Threats

None.

References

Sinker, C.A., Packham, J.R., Trueman, I.C., and Oswald, P.H., Perring, F.H. and Prestwood, W.V. (1985); Trueman, I., Morton, A. and Wainwright, M. (1995); Perring, F.H. and Walters, S.M.(eds.) (1962, 1976); Scannell, M.J.P. and Synnott, D.M. (1987); Webb,D.A., Parnell,J. and Doogue,D. (1996); Grigson, G. (1955, 1987); Grigson 1974; Mabey, R. (1972); Genders, R. (1971); Grime et al. 1988, 2007; Rackham 1980; Garrard & Streeter 1983; Gerard (1633); Britten & Holland (1886); Prior (1879); Johnson & Smith 1946; Gilbert-Carter 1964; Grieve 1931; Melderis & Bangerter 1955; Hultén & Fries 1986; Sell & Murrell 2006; Ridley 1930; Preston et al. 2002; Godwin 1975; Thompson et al. 1997; Hutchinson 1972;