Geranium purpureum

Geranium purpureum
Scientific classification
Kingdom:	Plantae
Clade:	Tracheophytes
Clade:	Angiosperms
Clade:	Eudicots
Clade:	Rosids
Order:	Geraniales
Family:	Geraniaceae
Genus:	Geranium
Species:	G. purpureum
Binomial name
Geranium purpureum Vill. [1]
Synonyms [2]
Homotypic synonyms Geranium robertianum proles purpureum(Vill.) Rouy Geranium robertianum subsp. purpureum(Vill.) Nyman Geranium robertianum purpureum(Vill.) Pers. Geranium robertianum var. purpureum(Vill.) DC. Robertium purpureum(Vill.) Fourr. Robertium vulgare var. purpureum(Vill.) Picard Heterotypic synonyms Geranium eginenseHausskn. & Sint. ex R.Knuth Geranium mediterraneumJord. Geranium minutiflorumJord. Geranium modestumJord. Geranium purpureum var. forsteriWilmott Geranium purpureum subsp. forsteri(Wilmott) H.G.Baker Geranium purpureum var. intricatum(Gren. ex Rouy) Graebn. Geranium purpureum var. mediterraneum(Jord.) Graebn. Geranium purpureum var. minutiflorum(Jord.) Loret & Barrandon Geranium purpureum var. modestum(Fourr.) Hausskn. Geranium purpureum var. modestum(Fourr.) Nyman Geranium purpureum f. subeglandulosumH.Lindb. Geranium robertianum var. incisumA.St.-Hil. Geranium robertianum f. intricatum(Gren. ex Rouy) Merino Geranium robertianum var. intricatumGren. ex Rouy Geranium robertianum subvar. mediterraneum(Jord.) Litard. Geranium robertianum var. mediterraneum(Jord.) Rouy Geranium robertianum f. minutiflorum(Jord.) Merino Geranium robertianum var. minutiflorum(Jord.) St.-Lag. Geranium robertianum f. modestum(Fourr.) F.N.Williams Geranium robertianum var. modestum(Fourr.) St.-Lag. Geranium robertianum subvar. modestum(Fourr.) Litard. Geranium robertianum var. parviflorumViv. Geranium robertianum var. rubricauleHornem. Geranium robertianum f. subeglandulosumH.Lindb. Geranium robertianum var. villarsianum(Jord.) Rouy & Foucaud Geranium semiglabrumJord. ex Boreau Geranium simileJord. ex Nyman Geranium villarsianumJord. Robertium minutiflorum(Jord.) Fourr. Robertium modestumFourr. Robertium semiglabrum(Jord. ex Boreau) Fourr. Robertium simileFourr.

Geranium purpureum, the little-robin, is a species of flowering plant in the geranium family Geraniaceae. It is native to Europe, Africa, and western Asia, and introduced on all continents except Antarctica. It is similar in appearance to Geranium robertianum , a close relative.

Description

Geranium purpureum is an annual (sometimes biennial), herbaceous, flowering plant. It has small flowers with 5  sepals and 5  petals, each petal being 6.3–8.4 mm long and 1.5–2.0 mm wide. The flower has 10  stamens, each with a yellow anther. In the center of the flower, a single fused style supports 5  stigmas. The fruit is a schizocarp, which splits into 5 one-seeded mericarps at maturity.

Identification

Flower with corolla approximately 7 mm in diameter

Geranium purpureum is often confused with Geranium robertianum , a close relative. The primary character that distinguishes the two species is flower size. The corolla of Geranium purpureum is approximately 7.5 mm in diameter while that of Geranium robertianum is at least twice that size (15–20 mm). ^[3] (For comparison, a U.S. dime is approximately 18 mm in diameter.) An identification key for genus Geranium in California distinguishes the two species as follows: ^[4]

• Geranium purpureum: ^[5] Petals (5.3–)6.3–8.4(–9.9) mm long, (0.8–)1.5–2.0(–2.6) mm wide; anthers yellow; middle leaf segment 5–20(–38)-lobed in distal half; mericarp with 1–4 collar-like rings at tip
• Geranium robertianum: ^[6] Petals (8.5–)10.5–12.5(–14.2) mm long, (2.1–)2.6–4.5(–6.1) mm wide; anthers purplish; middle leaf segment 16–37(–49)-lobed in distal half; mericarp with 1–2(–3) collar-like rings at tip

Other keys emphasize the hairs on the sepals as a distinguishing characteristic. ^[3] All keys include anther color but since both species have yellow pollen, plants can be difficult to distinguish based on anther color alone. Geranium purpureum and Geranium robertianum have chromosome numbers 2n = 32 and 2n = 64, respectively.

Taxonomy

Illustration of Geranium purpureum (lower righthand corner) published by Villars in 1789

Geranium purpureum was first described and named by the French botanist Domínique Villars in February 1786. ^{[1] [7]} A second description was published by Villars in June of the same year. ^[8] Taken together, he described a plant growing on the rocks with red leaves and a tiny reddish-pink corolla. In 1788, he further described the leaves as pinnately lobed with 5 segments. ^[9] Finally he published an illustration of Geranium purpureum in 1789. ^[10]

Geranium purpureumVill. is a member of Geranium section Ruberta in family Geraniaceae. ^[11] As of September 2025 ^[update] , the name Geranium purpureumVill. is widely accepted. ^{[2] [12]} Some authorities accept the name Geranium robertianum subsp. purpureum(Vill.) Nyman, ^[13] a homotypic synonym of Geranium purpureumVill. ^[14]

Distribution and habitat

Geranium purpureum growing along the tracks at the Wien Floridsdorf railway station in Vienna

Geranium purpureum ranges from Great Britain southeastward to the Caucasus, with native populations occurring as far south as central Africa. ^[2] Non-native populations occur on all continents except Antarctica. Introduced populations are often found along railway corridors. ^{[15] [16] [17]}

Ecology

Geranium purpureum can not survive winters with an average January temperature of 4 °C (39 °F) or less. ^[18]

References

1. "Geranium purpureumVill.". International Plant Names Index (IPNI). Royal Botanic Gardens, Kew; Harvard University Herbaria & Libraries; Australian National Botanic Gardens . Retrieved 4 September 2025.
2. "Geranium purpureumVill.". Plants of the World Online . Royal Botanic Gardens, Kew . Retrieved 2 September 2025.
3. Kim et al. (2019), p. 210.
4. Aedo, Carlos (2024). "Key page for Geranium". Jepson eFlora, Revision 13. University of California, Berkeley. Retrieved 4 September 2025.
5. Aedo, Carlos (2024). "Geranium purpureum". Jepson eFlora, Revision 13. University of California, Berkeley. Retrieved 4 September 2025.
6. Aedo, Carlos (2024). "Geranium robertianum". Jepson eFlora, Revision 13. University of California, Berkeley. Retrieved 6 September 2025.
7. Villars (1786a), p. 272.
8. Villars (1786b), pp. 72–73.
9. Villars (1788), p. 374.
10. Villars (1789), Plate XL.
11. Aedo (2017).
12. "Geranium purpureumVill.". World Flora Online. Retrieved 6 September 2025.
13. NRCS (6 September 2025), "Geranium robertianum L. ssp. purpureum (Vill.) Nyman", PLANTS Database, United States Department of Agriculture (USDA)
14. "Geranium robertianum subsp. purpureum(Vill.) Nyman". Plants of the World Online . Royal Botanic Gardens, Kew . Retrieved 6 September 2025.
15. "Little-Robin, Geranium purpureumVill.". Plant Atlas 2020. Botanical Society of Britain and Ireland. Retrieved 4 September 2025.
16. Eliáš (2011). sfnp error: no target: CITEREFEliáš2011 (help)
17. Kim et al. (2019).
18. Kim et al. (2019), pp. 213–214.

Bibliography

• Aedo, Carlos (2017). "Taxonomic Revision of Geranium sect. Ruberta and Unguiculata (Geraniaceae)". Annals of the Missouri Botanical Garden. 102 (3): 409–465. doi:10.3417/D-16-00016A. JSTOR   26573058.
• Eliáš Jr., Pavol (2011). "Geranium purpureumVill. — new alien species to the Slovak flora". Thaiszia Journal of Botany. 21: 21–28. Retrieved 2 September 2025.
• Kim, Hye-Won; Sun, Eun-Mi; Jung, Su-Young; Son, Dong Chan (2019). "Geranium purpureumVill.: A new casual alien plant in Korea". Korean Journal of Plant Taxonomy. 49 (3): 209–214. doi: 10.11110/kjpt.2019.49.3.209 .
• Villars, Domínique (February 1786a). Histoire des Plantes de Dauphiné, Vol. 1 . Retrieved 9 September 2025.
• Villars, Domínique (June 1786b). Flora Delphinalis . Retrieved 10 September 2025.
• Villars, Domínique (1788). Histoire des Plantes de Dauphiné, Vol. 3, Part 1 . Retrieved 9 September 2025.
• Villars, Domínique (1789). Histoire des Plantes de Dauphiné, Vol. 3, Part 2 . Retrieved 10 September 2025.

External links

• Leonard, Peter (13 May 2020). "Herb Robert (Geranium robertianum) and Little Robin (Geranium purpureum)" . Retrieved 4 September 2025.
• Leonard, Peter (9 August 2019). "Geraniums and Storksbills Key Features" . Retrieved 4 September 2025.
• Kartesz, John T. (2014). "Geranium purpureum". County-level distribution map from the North American Plant Atlas (NAPA). Biota of North America Program (BONAP). Retrieved 4 September 2025.
• "Flora of North America species comparison". Northwest Wildflowers. Retrieved 6 September 2025.