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.