Casuarina cunninghamiana Miq. subsp. cunninghamiana

Raab-Straube, Eckhard von & Raus, Thomas, 2024, Euro + Med-Checklist Notulae, 17, Willdenowia 54 (1), pp. 5-45 : 13

Casuarina cunninghamiana Miq. subsp. cunninghamiana – Fig. 5A.

A Tn: Tunisia: Mahdia, Rejiche, 35°28'41"N, 11°03'02"E, 27–30 m, roadsides, 7 Jul 2023, El Mokni (herb. Univ. Monastir).

– The casuarinas are a group of 90–96 species of trees and shrubs placed in four genera: Allocasuarina L. Johnson , Casuarina L., Ceuthostoma L. Johnson and Gymnostoma L. Johnson ( Wilson & Johnson 1989) . The genus Casuarina comprises c. 17 tree species ( Boland & al. 1996), mostly endemic to Australia, but with some representatives in SE Asia and the Pacific Islands. Chiefly due to their ability of nitrogen-fixing, fast-growing and tolerance to a wide range of adverse conditions including periodic waterlogging, drought, salt spray and highly saline soils, three main species, viz. C. cunninghamiana , C. equisetifolia L. and C. glauca Sieber ex Spreng. have widely been planted outside their native range ( National Research Council 1984). In N Africa, C. cunninghamiana and C. glauca have been reported as cultivated in Algeria (see, e.g., APD 2023; POWO 2023; Jury 2009 +; Belaid & al. 2022), the former also as cultivated in Tunisia ( Greuter & Domina 2015: 31). A fourth species, C. stricta Aiton , was reported as introduced to Morocco and Tunisia ( Dobignard & Chatelain 2011: 292). During the last few years, few juvenile specimens of C. cunninghamiana were discovered growing on roadsides in the region of Rejiche (Mahdia, CE Tunisia). The taxon seems to be naturalizing near some localities where it was successfully planted and can be considered currently as a casual alien; this is also its first report as a casual alien for N Africa. Tunisian collected material shows marcescent 8–10 teeth (reduced leaves), yellow at base, darker brown toward in the apex and is assigned to subsp. cunninghamiana (cf. Wilson & Johnson 1989: 106). R. El Mokni

Figures

Fig. 5. Alien Casuarina species in Tunisia – A: C. cunninghamiana subsp. cunninghamiana, juvenile plant. – B, C: C. glauca; B: ferruginous cylindric cones; C: branchlet apex. – A: Tunisia, Mahdia, Rejiche, 7 Jul 2023; B, C: ibid., Monastir, Monastir city, 18 Jul 2023, photographs by R. El Mokni.