Erodium

Erodium L’Hérit.

Erodium is a genus of about 60 species. Most are native to Europe, the Mediterranean area and Central Asia (with some additional species in Australia and South America). Two species are native in Belgium: Erodium cicutarium (L.) L’Hérit. (with two subspecies) and E. lebelii Jord.

Mericarps of Erodium are sharp pointed and have a distinct beak which in most species becomes twisted at maturity. They therefore easily attach to sheep wool and used to be among the most characteristic wool aliens in Belgium (along with, for instance, species of Medicago). Several species are weeds of arable land and occur far beyond their original distribution range (few as invasive weeds). Some species are cultivated as ornamentals but most are rare and hardly have been recorded as escapes so far in Belgium.

Erodium is a taxonomically complex genus. Numerous Belgian collections proved to be erroneously identified. In the absence of mature fruits most species cannot be reliably named.

1. Most leaves clearly pinnate with at least 5 leaflets === 2

1. Leaves simple (shallowly to deeply lobed) to ternate === 4

2. Apical pits of mericarps with sessile glands === Erodium moschatum

2. Apical pits of mericarps without sessile glands === 3

3. Rhizomatous perennial, without distinct stem (acaulescent). Petals 15-20 mm long. Fruit with column 40-70 mm long. Bracts herbaceous, entirely fused === E. manescavi

3. Annual, usually with distinct stem (caulescent). Petals 4-12 mm long. Fruit with column 10-40 mm long. Bracts scarious, free or fused at base only (native) === E. cicutarium and E. lebelii

4. Apical pit of mericarps with sessile glands === 5

4. Apical pit of mericarps without glands === 6

5. Upper petals distinctly bicolored (white with two reddish spots above the claw). Biennial or perennial === E. trifolium

5. All petals purplish. Annual === E. malacoides

6. Pit of mericarp without groove below. Leaves deeply 2-3-pinnatisect === E. stephanianum

6. Pit of mericarp with 1-3 deep grooves below. Leaves shallowly to deeply lobed or ternate === 7

7. Beak of fruit 15-35 mm long. Leaves shallowly lobed. Apical pit of mericarps with sessile glands === E. malacoides

7. Beak of fruit 40-100 mm long. Leaves usually deeply lobed or ternate. Apical pit of mericarps without glands === 8

8. Pit of mericarp with 2-3 grooves. Leaves pinnately lobed. Petals violet or purplish. Pedicels and sepals usually densely glandular === E. botrys

8. Pit of mericarp with a single groove. Leaves with 3 deep lobes to ternate. Petals bluish. Pedicels and sepals eglandular === E. crinitum

Additional aliens: Erodium brachycarpum (Godr.) Thell. [syn.: E. botrys var. brachycarpum Godr., E. obtusiplicatum (Maire, Weiller et Wilczek) J. Howell] (Medit.?[1], wool alien), E. chium (L.) Willd. (Medit., wool alien), E. ciconium (L.) L’Hérit. (Medit., wool alien), E. cygnorum Nees subsp. cygnorum (Austr., wool alien), E. cygnorum Nees subsp. glandulosum Carol. (Austr., wool alien) and E. salzmannii Delile [syn.: E. cicutarium subsp. jacquinianum (Fisch., C.A. Mey. et Avé-Lall.) Briq., E. jacquinianum Fisch., C.A. Mey. et Avé-Lall.] (Medit., wool alien).


[1] The initial area of origin of Erodium brachycarpum is very controversial. According to Sell & Murrell (2009) it is native of Australia, while Lawalrée (1964) places it in Chile. Clement & Foster (1994) give North Africa. Given its close relationship to Erodium botrys its native area most probably includes the Mediterranean area (see also Euro+Med PlantBase).

 


Literature:

Bruggeman C.J.M. (1964) Overzicht der in Nederland gevonden inheemse en adventieve Erodium-soorten. Gorteria 2(5): 49-55.

Carolin R.C. (1958) The species of the genus Erodium L’Hér. endemic to Australia. Proc. Linn. Soc. New South Wales 82: 92-100.

Clement E.J. & Foster M.C. (1994) Alien plants of the British Isles. BSBI, London: XVIII + 590 p.

El-Oqlah A.A. (1989) A revision of the genus Erodium L’Héritier in the Middle East. Feddes Repert. 100: 97-118.

Guittonneau G.-G. (1972) Contribution à létude biosystématique du genre Erodium L’Hér. dans le Bassin Méditerranéen occidental. Boissiera 20: 1-154.

Guittonneau G.-G. (2010) Aperçu sur la taxonomie, l’écologie et la phylogénie du genre Erodium L’Hér. dans le bassin méditerranéen. Available online at: http://www.tela-botanica.org/sites/botanique/fr/documents/biblio/articles_en_ligne/apercu_de_la_taxonomie_du_genre_erodium.pdf.

Jäger E.J., Ebel F., Hanelt P. & Müller G. (eds.) (2008) Rothmaler Band 5. Exkursionsflora von Deutschland. Krautige Zier- und Nutzpflanzen. Springer Verlag, Berlin: 880 p.

Knuth R. (1912) Geraniaceae. In: Engler A. (ed.), Das Pflanzenreich 53 (IV.129). Engelmann, Leipzig: 1-640.

Lawalrée A (1964) Geraniaceae. In: Robyns W. (ed.), Flore Générale de Belgique, vol. 4, fasc. 3. Jardin Botanique de l’Etat, Bruxelles: 239-286.

Sell P. & Murrell G. (2009) Flora of Great Britain and Ireland. Vol. 3 Mimosaceae – Lentibulariaceae. Cambridge University Press, Cambridge: XXVIII + 595 p.

Slavík B. (1997) Geraniaceae. In: Slavík B. (ed.), Kvĕtena České Republiky, vol. 5. Academia, Praha: 191-229.

Stace C. (2010) New flora of the British Isles, 3th ed.: XXXII + 1232 p. Cambridge University Press.

Venter H.J.T. & Verhoeven R.L. (1990) The genus Erodium in southern Africa. S. Afr. J. Bot. 56(1): 79-92.

Webb D.A. & Chater A.O. (1968) Erodium. In: Tutin T.G. & al. (eds.), Flora Europaea, volume 2. Cambridge University Press, Cambridge: 199-204.

Yeo P.F. (1997) Erodium. In: Cullen J. & al. (eds.), The European Garden Flora, vol. 5. Cambridge University Press, Cambridge: 50-56.

 

Taxonomic name: 
Scratchpads developed and conceived by (alphabetical): Ed Baker, Katherine Bouton Alice Heaton Dimitris Koureas, Laurence Livermore, Dave Roberts, Simon Rycroft, Ben Scott, Vince Smith