Blackstonia perfoliata

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

Blackstonia perfoliata (L.) Huds.

(≡ Chlora perfoliata L.)

– Ag: The first surveys of the genus Blackstonia Huds. (≡ Chlora Adans. ) in N Africa during the 18 th century ( Poiret 1789: 158; Desfontaines 1798: 327) only refer to B. perfoliata sensu lato (as C. perfoliata ). After the description of B. grandiflora (Viv.) Pau by Viviani (1830: 4, as C. grandiflora ), the Algerian floras only considered that taxon ( Munby 1847: 40; 1859: 21; 1866: 23). At the end of the 19 th century, Battandier (1890: 590, as C. perfoliata) reintroduced the name B. perfoliata for Algeria, however with doubt, saying “des échantillons de la province de Constantine m’ont paru s’y rapporter”. Nevertheless Julien (1894: 186) accepted B. perfoliata (as C. perfoliata ) for Algeria in addition to the common B. grandiflora . Battandier (1890: 590) claimed the occurrence of B. perfoliata also for Tunisia, but Bonnet & Barratte (1896: 288, as C. imperfoliata L. f.) argued that the latter record concerned B. imperfoliata (L. f.) Samp. Accordingly, Battandier & Trabut (1905: 228) then accepted B. imperfoliata as the second species for Tunisia, but not for Algeria where they considered only the occurrence of B. grandiflora . Battandier (1910: 63) also confirmed B. imperfoliata for Tunisia, but considered B. perfoliata to be deleted from the flora of Algeria. On the contrary, Quézel & Santa (1963: 741) reconsidered, additionally to the common B. grandiflora (as B. perfoliata subsp. grandiflora (Viv.) Maire), the presence of B. perfoliata in Algeria (as B. perfoliata subsp. “ eu-perfoliata ” Maire). Pottier-Alapetite (1981: 699) forgot to mention the historical presence of B. imperfoliata but added B. perfoliata (subsp. “ eu-perfoliata ” Maire) to the flora of Tunisia, based on three collections (two from herself and one from Cuénod). Finally, Le Floc’h & al. (2010: 209) reconsidered the historical presence of B. imperfoliata (as B. perfoliata subsp. imperfoliata ) in Tunisia, but did not consider the possibility of any misidentification concerning B. perfoliata subsp. perfoliata . As a consequence, they accepted three Blackstonia taxa for Tunisia (followed by Marhold 2011+c). Flowering plants illustrated on the sharing network iNaturalist by one of us ( AS) allowed the other (EV) to identify them as B. acuminata (W. D. J. Koch & Ziz) Domin (see preceding entry). None of the main, independent backbone databases on the N African flora gives this species for Algeria (nor Tunisia). We carried out a digital search on specimens of the genus Blackstonia from “Afrique du Nord” stored in the herbarium P, which gave 217 results (https://science.mnhn.fr/institution/mnhn/collection/p /item/list?specificEpithet =imperfoliata &secteur=AFN& genus= Blackstonia , accessed 3 Jan 2023). Among them, 11 sheets from the Canaries, Morocco and Tunisia (but none from Algeria) are correctly sorted under B. imperfoliata , 133 sheets from all three N African countries are correctly sorted under B. grandiflora and 72 sheets are sorted under “ B. perfoliata ”; only seven of them, all from Morocco, effectively concern B. perfoliata s.str., a further three from Morocco fall within the variability of B. acuminata , whereas the majority shows specimens of B. grandiflora from all three countries (mostly labelled “subsp./ var. grandiflora ”). As a consequence, we cannot confirm any specimen of B. perfoliata s.str. from Algeria, and this taxon should therefore be retracted from the national checklist. E. Véla & A. Saci