Geum - WikiHQ

Geum (L.) , commonly called avens, is a flowering plant genus of about 60 accepted species and hybrids, within the Rosaceae family in the order of Rosales, in the major group angiosperms.

The species of the genus are widely distributed across Europe, Asia, North and South America, Africa, and New Zealand. They are closely related to Potentilla and Fragaria. From a basal rosette of leaves, they produce flowers on wiry stalks, in shades of white, red, yellow, and orange, in midsummer.

Description

Species within Geum genus are herbaceous perennials, often rhizomatous and sometimes stoloniferous. 10-120 cm in height, though rarely above 60 cm, erect and simple stem, 1-5, either glabrous or hairy.

, growing in a mounding habit. Geum species are evergreen except where winter temperatures drop below .

The most distinctive feature of many members of Geum is an geniculate-jointed style, that forms a hook. Though, this is not true for all species within the genus.

Fruit

thumb|200px|[[Geum vernum developing fruit]]

thumb|right|200px|Fruit in Geum genus

The plant produces aggregated achenes, (2–)20–250(–450), 2–4.5 mm long, hairy, and sometimes stipitate.

Distribution and ecology

Most of the species of the Geum genus occur in temperate and arctic-alpine regions, and several species are cultivated.

Geum has a wide distribution mostly located in the northern hemisphere. They are native to Africa, North America, Mexico, South America, Eurasia, Pacific Islands (New Zealand), Australia.

For instance, Geum urbanum is used as food by the larvae of the grizzled skipper Pyrgus malvae as well as Stigmella splendidissimella and Stigmella pretiosa,

while Geum rivale is host to Geina didactyla and Stigmella pretiosa, among others.

thumb|200px|Bumblebee in Geum rivale

Flowers of Geum species also attract bees.

Several fungi lives on Geum species. The rost fungi Puccinia can be found on at least Geum reptans., while 51 ascomycete fungi from the classes Sordariomycetes,

Leotiomycetes, Dothideomycetes and Eurotiomycetes have been found on Geum peckii.

Further, endosymbionts have been found in roots of Geum species. One example is the nitrogen-fixing bacteria genus Rhizobium and the plant growth-promoting rhizobacteria Pseudarthrobacter sp. that have been extracted from the roots of Geum aleppicum.

Utility to humans

Geum is used as a ornemental plant, as its flowers resemble small roses, and it has been a recurring—although not among the most commonly cultivated—genus in flower beds and ornamental gardens.

The cultivar 'Mrs J. Bradshaw' (with orange flowers) has the Royal Horticultural Society's Award of Garden Merit.

The UK National Collection of geums is held at Brickwall Cottage Garden and Nursery in Frittenden, Kent.

Moreover, Geum has long held medicinal importance. Species within the genus have traditionally been used in folk medicine as anti-inflammatory, antiseptic, diuretic, and astringent remedies. Contemporary pharmacological research has supported several of these traditional uses. According to Mo et al. (2025), the high tannin content found in Geum species is associated with anti-inflammatory, antioxidant, antimicrobial, cardioprotective, and antiviral activities.

Etymology and taxonomy

The name Geum has been found in literature dating back to AD 77. The name Geum originates from the words geyo or geno, which is latinized Greek for "taste" referencing the roots of the plant, which smell like cloves when crushed.

Taxonomic history of Geum

The genus was first described by Gaspard Bauhin as Caryophyllata in 1623.

Carl Linnaeus later assigned the genus its current name, Geum, in Species Plantarum (1753).

Over the past centuries, several scientists have changed the classification of the genus, included or removed species. These classifications were maily based on morphological features, primarily separating species due to deciduous or non-deciduous styles, or the presence of a fish-hook fruit type. Some of the contributors were Scheutz (1870), Focke (1894), Greene (1899), Rydberg (1913), Hultén (1929) and Bolle (1933).

Gajewski (1958) described the genus as a complex of polyploid species with high crossability between species, permitting the formation of numerous hybrids. Due to several different genome combinations, the genus was divided into distinct groups of species that differed in morphology and distribution, although all species were still classified within a single genus. Gajewski suggested that allopolyploidy has been a key factor affecting the speciation and evolution of the subgenus Geum, between the ancestors Waldsteinia and Geum montanum.

The delimitation and classification of Geum have continued to change several times during the last decades. Still, ongoing genetic research results in changes in both species and genus levels. W. Gajewski (1958) described Geum as a genus within the tribe Geeae together with the closely related genera Waldsteinia and Coluria. The tribe Geeae formed the subfamily Dryadoideae together with Cercocarpeae and Dryadeae within the family Rosaceae. The number of chromosomes seemed to differ between groups, where the woody plants with wind-dispersal strategy had a basic chromosome number of 9, while the herbacious, more widley distributed and animal-disperse adapted species - including Geum species - instead had a basic chromosome number of 7.

This difference in basic chromosome number was further investigated by Wallaart (1980) that found a correlation between basic chromosome number of 9 and presence of sorbitol. Hebda and Chinnappa (1994) could further support that theory by identifying the common characteristic of striate microperforate pollen in Geum, Coluria, Fallugia, Orthurus, and Waldstein - all containing a basic chromosome number of 7.

In addition to that theory, Morgan et al. (1994) added the presence of nitrogen-fixing bacteria in root nodules as a synapomorphy that divided species with 7 or 9 in basic chromosome number.

In recent molecular phylogenetic research, J. E. E. Smedmark et al. (2003) have tested the allopolyploidy hypothesis by Gajewski as well as explored the relationships within the group formerly known as Dryadeae, based on DNA sequences from chloroplast trnL-trnF region and ITS of nuclear ribosomal DNA. Their result does not support any of the previous circumscriptions of Geum as a monophyletic group or earlier suggested segregate genera, though some indications for allopolyploidy are found in the results. They suggest a delimitation of herbaceous perennials with a rosette of basal leaves in

the tribe Colurieae as Geum in a broad sense , which is supported by the comparative genomic analyses of Fu et al. (2025).

Current classification of Geum

Geum belongs to the family Rosaceae, in the order Rosales. The closest related genera to Geum are Coluria, Fallugia and Waldsteinia. It also belongs to the tribe Rosideae, formerly known as Dryadeae. Geum form this subfamily together with about 38 other generas, including for instance Alchemilla and Rosa (plant). Some species within the subfamily are shrubs but most of them are herbaceous perennials, most frequently occurring in the northern hemisphere. Though, no morphological synapomorphies have been identified for Dryadeae.

The discussion on what to include or not in the genus of Geum is ongoing but a key characteristic that are more or less agreed upon is the fish-hook fruit type that almost all species within the genus have in common, though Geum vernum is an exception.

Species list

, Plants of the World Online accepted the following (46) species and (15) hybrids:

Geum aequilobatum K.M.Purohit & Panigrahi
Geum aleppicum Jacq. - Yellow avens or common avens
Geum andicola (Phil.) Reiche
Geum × aurantiacum Fr. ex Scheutz - Orange avens
Geum boliviense Focke
Geum brevicarpellatum F.Bolle
Geum bulgaricum Pančić
Geum calthifolium Sm.
Geum canadense Jacq. - White avens
Geum capense Thunb.
Geum × catlingii J.-P.Bernard & R.Gauthier - Catling's avens
Geum coccineum Sm. - Dwarf orange avens
Geum x convallis M.P.Wilcox
Geum x cortlandicum M.Hough - Cortland Avens
Geum elatum Wall. ex G.Don - High Avens
Geum geniculatum Michx. - Bent avens
Geum glaciale Adams ex Fisch. - Glacier Avens
Geum x gonzaloi J.L.Lozano & Serra
Geum × gudaricum Mateo & J.L.Lozano
Geum x hainesianum M.Hough, A.V.Gilman & Chapm.-Lam
Geum heterocarpum Boiss.
Geum hispidum Fr.
Geum × intermedium Ehrh. - Hybrid Avens
Geum japonicum Thunb. - Asian herb bennet
Geum kokanicum Regel & Schmalh.
Geum laciniatum Murray – Rough avens
Geum latilobum Sommier & Levier
Geum × macneillii J.-P.Bernard & R.Gauthier
Geum × macranthum (Kearney ex Rydb.) B.Boivin
Geum macrophyllum Willd. - Largeleaf avens or large-leaved avens
Geum macrosepalum Ludlow
Geum magellanicum Comm. ex Pers.
Geum × meinshausenii Gams
Geum mexicanum Rydb.
Geum molle Vis. & Pančić
Geum montanum L. – Alpine avens
Geum peckii Pursh – Mountain avens or Peck's avens
Geum peruvianum Focke
Geum × pratense Pau
Geum × pulchrum Fernald
Geum pyrenaicum Mill.
Geum quellyon Sweet - Scarlet avens or Chilean avens
Geum radiatum Michx. – Spreading avens or Appalachian avens
Geum reptans L. – Creeping avens
Geum rhodopeum Stoj. & Stef.
Geum riojense F.Bolle
Geum rivale L. - Water avens or purple avens
Geum rossii (R.Br.) Ser. – Alpine avens
Geum roylei Wall. ex F.Bolle - Himalayan Avens
Geum rubrum (Ludlow) Khuroo, K.Hussain & Gulzar - Red avens
Geum schofieldii Calder & Roy L.Taylor Haida Gwaii avens
Geum sikkimense Prain
Geum speciosum (Albov) Albov
Geum × spurium C.A.Mey.
Geum × sudeticum Tausch
Geum sunhangii D.G.Zhang, T.Deng, Z.Y.Lv & Z.M.Li
Geum sylvaticum Pourr.
Geum triflorum Pursh – Prairie smoke or three-flowered avens
Geum urbanum L. - Wood avens or herb Bennet
Geum vernum (Raf.) Torr. & A.Gray – Spring avens
Geum virginianum L. – Cream avens or Virginia avens

For a more detailed list see List of Geum species.

References

External links

Jepson Manual Treatment, University of California
Ontario Wildflowers: Avenses Group