Opuntia puberula Pfeiff.

Raab-Straube, Eckhard von & Raus, Thomas, 2022, Euro + Med-Checklist Notulae, 15, Willdenowia 52 (2), pp. 273-299 : 276-278

Opuntia puberula Pfeiff. – Fig. 2.

N It : Italy: Molise, Campobasso, municipality of Guglionesi , 41°52'22.61''N, 14°53'38''E, 53 m, on a chalky SE facing rock wall, 31 May 2022, Palermo (photo) ; Toscana,

Livorno, Grotti, municipality of Rosignano Marittimo, 43°23'49.75''N, 10°28'46.58''E, 44 m, subspontaneous along a wall, 15 Sep 2016, Lazzeri (photo). – Opuntia puberula can be considered an easily misidentified and therefore overlooked taxon, which closely resembles O. microdasys (Lehm.) Pfeiff. by the relatively small size of both the whole plant and the pads and by the areoles being situated close together. However, O. puberula can be distinguished from O. microdasys mainly by the presence of small and slender, reflexed and spreading spines on some areoles of both pads and hypanthia ( Fig. 2C), the more oblong shape of the pads (vs usually elliptic-obovate in O. microdasys ), the consistently yellow glochids (vs sometimes white or reddish glochids in O. microdasys ) and the areoles being more distant from each other. The two taxa, despite their morphological similarities, seem to be phylogenetically distant, with O. puberula unexpectedly placed among the species previously attributed to the genus Nopalea Salm-Dyck , while O. microdasys is nested in the “ Basilares clade” ( Majure & al. 2012). Opuntia puberula has long been considered a synonym of O. decumbens Salm-Dyck , following Britton & Rose (1919), who stated that the cultivated plants attributed to O. puberula were actually something distinct and that this latter species should be considered a synonym of O. decumbens . This treatment was followed again in Galasso & al. (2018), in which O. decumbens was excluded from Italy. However, O. puberula and O. decumbens are clearly distinct, as was shown, e.g., by Bravo-Hollis (1978) and Sánchez & Villaseñor (1994) and was also accepted in the most recent checklist of Cactaceae ( Korotkova & al. 2021). One of the differential characters is the extremely short and thin spination in O. puberula vs longer and stouter spination in O. decumbens , when present ( Pineda & Oyuela 2020). Opuntia puberula has so far been reported only from Spain ( Guillot 2008), while it cannot be excluded that it is more widespread in the Euro-Mediterranean area. On the basis of our observations in the field, O. puberula is to be considered as naturalized in Italy.

V. Lazzeri & D. Palermo