1. Erodium botrys (Cav.) Bertol. (Medit.) – A rare and much decreasing, always ephemeral alien. Apparently first collected in 1826 without further details. Erodium botrys used to be one of the more typical wool aliens in the valley of river Vesdre near Verviers (Visé 1942, 1958). It was seen numerous times and often in abundance since 1894 and – unlike most other wool aliens – still regularly occurred in the beginning of the 1970’s. It also was one of the few wool aliens that also was observed further downstream from Verviers, for instance in Trooz (1903). Only exceptionally seen elsewhere, for instance in 1922 in Watermaal-Bosvoorde (Brussel) and in 1938 in Franchimont, twice without obvious vector of introduction. Also repeatedly seen on the Dutch side of river Maas (Bruggeman 1964, van Ooststroom & Mennema 1972), obviously originating from the woollen mills further upstream near Verviers.
Erodium botrys was often confused with E. ciconium in Belgian herbaria. However, mericarps are very different: apical pits are surrounded by 2-3 distinct grooves in the former while these are absent in the latter.
Lawalrée (1964) ascribed one Belgian collection to var. brevicaule Rouy et Fouc., an acaulescent variety, but this taxon seems to have no taxonomic value.
Erodium brachycarpum was formerly recorded as a wool alien (see under “Additional aliens”). According to most recent authors (including the Euro+Med PlantBase) it is better synonymised with Erodium botrys.
Bruggeman C.J.M. (1964) Overzicht der in Nederland gevonden inheemse en adventieve Erodium-soorten. Gorteria 2(5): 49-55.
Guittonneau G.-G., Montserrat P. & Villar L. (1987) L’Erodium brachycarpum (Godron) Thell., espèce méditerranéenne méconnue de la série évolutive de l’E. botrys (Cav.) Bertol. (Geraniaceae). Candollea 42: 417-425.
Lawalrée A (1964) Geraniaceae. In: Robyns W. (ed.), Flore Générale de Belgique, vol. 4, fasc. 3. Jardin Botanique de l’Etat, Bruxelles: 239-286.
Slavík B. (1996a) Erodium botrys – a new species in the flora of the Czech Republic. Preslia 67: 305-309.
Van Ooststroom S.J. & Mennema J. (1972) Adventieven langs de Maas in Limburg, VI. Natuurhist. Maandbl. 61: 42-44.
Visé A. (1942) La flore adventice de la région de Verviers. Lejeunia 6: 99-119.
Visé A. (1958) Florule adventice de la vallée de la Vesdre. Bull. Soc. Roy. Bot. Belg. 90: 287-305.