Orobanche gracilis Smith

Mokni, Ridha El, Domina, Gianniantonio & Barone, Giulio, 2023, New records of the genus Orobanche L. (Orobanchaceae) to the Tunisian flora with lectotypification of the name O. rapum-genistae Thuill., Adansonia (3) 45 (5), pp. 73-81 : 74-79

3. Orobanche gracilis Smith

Transactions of the Linnean Society of London 4: 172 ( Smith 1798).

LECTOTYPE. — Designated by Foley 2001: 231, Herb. Smith 1087.11 (no. 1 LINN photo!) .

GENERAL DISTRIBUTION. — The range of this species extends almost continuously throughout the Mediterranean area in southern Europe from the Iberian Peninsula in the west to the Black Sea coast in the east, including Anatolia and the Caucasus Mountains. In the North it reaches France, Switzerland, Germany, Austria, and South West Slovakia ( Kreutz 1995; Zázvorka 1997; Pusch et al. 2001; Sánchez Pedraja et al. 2005; Domina & Arrigoni 2007; Domina & RaabStraube 2010). In North Africa, it occurs in Morocco and Algeria (Domina & Raab-Straube 2010; Dobignard & Chatelain 2013), it is here the first record for the Tunisian flora.

DISTRIBUTION IN TUNISIA. — Pine forests of Le Kef, area of ‘ Dir’ (NW Tunisia).

HOSTS IN TUNISIA. — On Cytisus laniger DC. ( Fig. 2 ) and Genista cinerea (Vill.) DC. ( Fig. 3 ). The individuals growing on Genista cinerea have the characters used to distinguish O. gracilis var. deludens (Beck) A. Pujadas (synonym O. austrohispanica M. J. Y. Foley ) the corolla keeled along dorsal line, reddish veined, pale coloured corollas lacking the shiny red interior typical of O. gracilis s.s. and almost glabrous filaments ( Román et al. 2007). As already noted for Orobanche crenata Forrsk. ( Domina 2018) this kind of variability of the parasite could be influenced by the different hosts.

HABITAT. — On roadsides and edges within pine forests, on clayey soils of sunny places.

FLOWERING PERIOD. — April to May.

SPECIMEN SEEN. — Tunisia. Orobanche gracilis var. gracilis, Le Kef North, 36°10’14”N, 008°43’55”E, 625 m a.s.l., on Cytisus laniger , 30.IV.2019, G. Domina & R. El Mokni s.n. (PAL, Herb. Univ. Monastir). — O. gracilis var. deludens, Le Kef North, 36°10’14”N, 008°43’55”E, 625 m a.s.l., on Genista cinerea , 30.IV.2019, R. El Mokni s.n. (Herb. Univ. Monastir).

Figures

FIG. 2. — Orobanche gracilis Sm. in north-western Tunisia: A, habit of a flowering plant in its natural habitat parasiting on Cytisus laniger DC.; B, details of scales, inflorescence and opened flowers. Photographs: R. El Mokni, 30.IV.2019.

FIG. 3. — Orobanche gracilis Sm. in north-western Tunisia: A, habit of a flowering plant in its natural habitat, parasiting on Genista cinerea (Vill.) DC.; B, details of scales, inflorescence and opened flowers. Photographs: R. El Mokni, 30.IV.2019.