Geum urbanum, also known as wood avens, herb Bennet, colewort, clove root and St. Benedict's herb (Latin: herba benedicta), is a perennial plant in the rose family (Rosaceae), which grows in shady places (such as woodland edges and near hedgerows) in the temperate regions of Eurasia and North America.
Description
Geum urbanum is a downy perennial herb with a short, thick rhizome and thin wiry stems, reaching up to . The rhizome is purple in cross-section.
The leaves, which vary considerably in form depending on their position and local growth conditions, are pinnate, with 2–3 pairs of unequal lateral leaflets measuring long, and one large terminal three-lobed leaflet that is cuneate to cordate at the base. The upper leaves on the stem are trifoliate, consisting of three long narrow leaflets, or undivided. The stipules, measuring 4 x 3 cm, are as wide as long. The flowers are 1–2 cm in diameter, having five bright yellow petals clearly separated from a calyx divided into 5 large and 5 small segments.
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(MHNT) Geum urbanum - Buds and flower.jpg| Buds and flower
(MHNT) Geum urbanum - flower.jpg|Flower
(MHNT) Geum urbanum - Fruit.jpg|Immature fruit
INaturalist observation-256614716 photo-460142656.jpeg|foliage
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Taxonomy
Geum urbanum hybridizes fairly regularly with Geum rivale (water avens), as they are closely related and cooccur. In fact, the phenomenon is so conspicuous that hybrids were once treated as a separate species named Geum intermedium <small>Ehrh.</small>
It has been introduced in North America, where it forms natural hybrids with Geum canadense (= Geum ×catlingii <small>J.-P. Bernard & R. Gauthier</small>).
Both G. urbanum and its hybrids show hexaploidy, with chromosome number 2n = 42.
Etymology
The common name avens is derived from the Latin Avencia, in turn from the medieval Latin avantia or avence. The other English name Herb Bennet is a corruption of the old herbalist name Herba benedicta, meaning blessed herb.
The generic name Geum originated from the Greek geno, a word meaning to yield a pleasant aroma, in reference to the root’s strong clove-like smell when freshly dug up.
Distribution
Geum urbanum is found throughout Europe (its areas are more scattered in southern Iberia and in Russia, and it is completely absent from northern Scandinavia, Iceland, the Faroe Islands, Shetland, Malta, the Balearic and the Aegean islands). It also occurs in the Atlas Mountains of Morocco, Algeria and Tunisia, in Turkey and the Levant, the Caucasus and the Armenian Highlands, around the Alborz mountains in Iran, and less extensively in western Siberia and in the mountains of Central Asia up to the Western Himalayas.
Ecology
thumb|Fruits attached to the fur of a [[labrador retriever]]
G. urbanum is a common, typically lowland plant favouring dry semi-natural broadleaved woodland, scrub, hedgerows, and waysides on well-drained soils. It sometimes also grows in open disturbed habitats rich in soil nitrogen, occurring as a garden weed. The plant has a moderate shade tolerance and is absent from open grassland communities where it appears unable to compete with other species Some of its basal rosette leaves are produced in October, overwinter in the vegetative state, remain green and are photosynthetically active during winter.
G. urbanum has been observed to be infected by various fungal pathogens, including downy mildew species in Peronospora, the powdery mildew Podosphaera aphanis sensu lato, and Ramularia species, of which the latter causes the formation of pale spots on the leaves.
Uses
The leaves can be cooked like spinach. and are used as a spice in soups and also for flavouring ale. For example, the Augsburg Ale is said to owe its peculiar flavour to the addition of a small bag of avens inside each cask. The fresh root imparts a pleasant clove-like flavour to the liquor, preserves it from turning sour, and adds to its wholesome properties. but there is no evidence that it makes any difference.
A cordial against the plague was made by boiling the roots in wine. English botanist John Gerard recommended a "decoction made in wine against stomach ills and bites of venomous beasts". Because of its digestive tonic properties, chewing of the root was also recommended for foul breath.