Clarifying the nomenclatural uncertainties surrounding Cistus pouzolzii Delile, C. × florentinus Lam., and C. × varius Pourr. (Cistaceae)

Through the typification of C. × varius Pourr., we conclude, as Demoly previously stated, that the name C. varius Pourr. should definitively be considered a later synonym of C. × florentinus Lam., the priority name for naming the hybrid between C. monspeliensis L. and C. salviifolius L. Finally, the lectotypification of C. pouzolzii L. led us to conclude that it is an independent species unrelated to the aforementioned hybrid.

RÉSUMÉ Clarification des incertitudes nomenclaturales entourant Cistus pouzolzii Delile, C. × florentinus Lam. et C. × varius Pourr. (Cistaceae). Trois noms du genre Cistus L. sont analysés d’un point de vue nomenclatural: Cistus pouzolzii Delile, C. florentinus Lam. et C. × varius Pourr.

Les lectotypes correspondants pour C. pouzolzii Delile et C. × varius sont désignés sur la base des spécimens conservés dans l’herbier du Muséum national d’Histoire naturelle de Paris, à P. Le nom C. florentinus Lam. a été étudié par Demoly qui, en 1994, a désigné son lectotype à partir d’un spécimen conservé dans l’herbier P. Grâce à la typification de C. × varius Pourr., nous concluons, comme Demoly l’a déjà indiqué, que le nom C. × varius doit être définitivement considéré comme un synonyme ultérieur de C. florentinus Lam., le nom prioritaire pour nommer l’hybride entre C. monspeliensis L. et C. salviifolius L. Enfin, la lectotypification de C. pouzolzii Delile nous a permis de conclure qu’il s’agit d’une espèce indépendante non liée à l’hybride susmentionné.

MOTS CLÉS Cistaceae, Cistus, hybride, bassin méditerranéen, lectotypification. INTRODUCTION The genus Cistus L., including Halimium (Dunal) Spach, contains 34 accepted species (48 taxa considering subspecies) and approximately 80 nothotaxa, however, more than 850 names have been published (Dunal 1824; Sweet 1825 -1830; Spach 1836; Grosser 1903; Dansereau 1939; Guzmán & Vargas 2005; POWO 2024; WFO 2024). Typification through the study of protologues and original materials is essential for the correct application of names and their synonyms.

Cistus pouzolzii Delile is a western Mediterranean species, previously known from southern France, Algeria, Morocco, and recently found in the Iberian Peninsula (Sánchez-Gómez et al. 2024). Morphological (e.g., Grenier & Godron 1847; Pouzolz 1857; Willkomm 1857 -1863; Gard 1912; Warburg & Warburg 1930) and genetic studies (e.g., Guzmán & Vargas 2005, 2009, 2010; Guzmán et al. 2009; Civeyrel et al. 2011; Totta et al. 2016; Sánchez-Gómez et al. 2024) confirm that C. pouzolzii is a distinct species.

However, since the description of C. pouzolzii (Delile 1840), different names have been used to refer to this species (e.g, C. varius Pourr., pro sp. and pro hybr. as C. × varius and C. × florentinus Lam., as a hybrid between C. crispus L. and C. monspeliensis L.). The name C. varius Pourr. was considered a priority name for C. pouzolzii for a long time (Clos 1858; Timbal-Lagrave 1875; Willkomm 1878; Battandier &Trabut 1888; Warburg & Warburg 1930; Dansereau 1939; Warburg 1968; Greuter et al. 1984).

However, neither the locality nor the description of Pourret’s protologue (1788) fit the characteristics of C. pouzolzii (Rouy & Foucaud 1895; Aubin 1985, 1986, 1990). Grosser (1903: 30) also synonymised it with C. × varius, but considered it as a hybrid between C. crispus and C. monspeliensis L., an opinion followed by Martín-Bolaños & Guinea (1949: 169-173) and also suggested as a possibility by Warburg (1968). M. Bornet performed artificial crosses, however, this hybrid could not be obtained (Gard 1907, 1910, 1912).

Furthermore, it was not found in nature until the recent description of the supposed hybrid C. pintii F. M. Vázquez Pardo (Bellard & Hervás 2021; Tejerina & Vázquez 2023). On the other hand, C. × varius has been interpreted as a hybrid between C. monspeliensis L. and C. salviifolius L. and in this case, the priority name is C. × florentinus (Lamarck 1786; Rouy & Foucaud 1895; Dobignard & Chatelain 2011; Tison & de Foucault 2014).

Cistus × florentinus is a relatively common hybrid in the Mediterranean region when both parental species are present. It has also been introduced as an ornamental plant in various parts of the world (Şen & Duman 2021; GBIF 2023). This hybrid is often fertile and backcrosses with the parent species (Dansereau 1943), which have been recently typified (Ferrer-Gallego et al. 2013).

Some of the Cistus species described by Lamarck or Pourret have also been typified (Carazo & Jiménez 1989; Demoly 2002, 2006; Ibáñez et al. 2009; Ferrer-Gallego 2016; Tejerina & Vázquez 2021). However, the application of the name C. × varius, its confusion with C. pouzolzii, and its relationship with C. × florentinus still need to be clarified. The discovery of original material and the typification of these three names have allowed for the correct application of the names and clarified a nomenclatural debate that has lasted for over 200 years.

The genus Cistus L., including Halimium (Dunal) Spach, contains 34 accepted species (48 taxa considering subspecies) and approximately 80 nothotaxa, however, more than 850 names have been published (Dunal 1824; Sweet 1825 -1830; Spach 1836; Grosser 1903; Dansereau 1939; Guzmán & Vargas 2005; POWO 2024; WFO 2024). Typification through the study of protologues and original materials is essential for the correct application of names and their synonyms.

Cistus pouzolzii Delile is a western Mediterranean species, previously known from southern France, Algeria, Morocco, and recently found in the Iberian Peninsula (Sánchez-Gómez et al. 2024). Morphological (e.g., Grenier & Godron 1847; Pouzolz 1857; Willkomm 1857 -1863; Gard 1912; Warburg & Warburg 1930) and genetic studies (e.g., Guzmán & Vargas 2005, 2009, 2010; Guzmán et al. 2009; Civeyrel et al. 2011; Totta et al. 2016; Sánchez-Gómez et al. 2024) confirm that C. pouzolzii is a distinct species.

However, since the description of C. pouzolzii (Delile 1840), different names have been used to refer to this species (e.g, C. varius Pourr., pro sp. and pro hybr. as C. × varius and C. × florentinus Lam., as a hybrid between C. crispus L. and C. monspeliensis L.). The name C. varius Pourr. was considered a priority name for C. pouzolzii for a long time (Clos 1858; Timbal-Lagrave 1875; Willkomm 1878; Battandier &Trabut 1888; Warburg & Warburg 1930; Dansereau 1939; Warburg 1968; Greuter et al. 1984).

However, neither the locality nor the description of Pourret’s protologue (1788) fit the characteristics of C. pouzolzii (Rouy & Foucaud 1895; Aubin 1985, 1986, 1990). Grosser (1903: 30) also synonymised it with C. × varius, but considered it as a hybrid between C. crispus and C. monspeliensis L., an opinion followed by Martín-Bolaños & Guinea (1949: 169-173) and also suggested as a possibility by Warburg (1968). M. Bornet performed artificial crosses, however, this hybrid could not be obtained (Gard 1907, 1910, 1912).

Furthermore, it was not found in nature until the recent description of the supposed hybrid C. pintii F. M. Vázquez Pardo (Bellard & Hervás 2021; Tejerina & Vázquez 2023). On the other hand, C. × varius has been interpreted as a hybrid between C. monspeliensis L. and C. salviifolius L. and in this case, the priority name is C. × florentinus (Lamarck 1786; Rouy & Foucaud 1895; Dobignard & Chatelain 2011; Tison & de Foucault 2014).

Cistus × florentinus is a relatively common hybrid in the Mediterranean region when both parental species are present. It has also been introduced as an ornamental plant in various parts of the world (Şen & Duman 2021; GBIF 2023). This hybrid is often fertile and backcrosses with the parent species (Dansereau 1943), which have been recently typified (Ferrer-Gallego et al. 2013).

Some of the Cistus species described by Lamarck or Pourret have also been typified (Carazo & Jiménez 1989; Demoly 2002, 2006; Ibáñez et al. 2009; Ferrer-Gallego 2016; Tejerina & Vázquez 2021). However, the application of the name C. × varius, its confusion with C. pouzolzii, and its relationship with C. × florentinus still need to be clarified. The discovery of original material and the typification of these three names have allowed for the correct application of the names and clarified a nomenclatural debate that has lasted for over 200 years.