These statements aim to determine whether the term Moroccan Macaronesian sector should be retained or discarded; the scientific evidence is presented in chronological order.
Based on the presence of Macaronesian species or vicariants of Macaronesian species, Braun-Blanquet and Maire (1924) were the first to consider the presence in Morocco of a Macaronesian enclave, located almost exclusively in the Argan tree sector (Braun-Blanquet and Maire, loc. Cit., p. 64). To explain the affinities between the southern Moroccan Atlantic coast and the Canary Islands, they assumed a direct connection between the islands and the continent, certainly during the Tertiary period. It is now known that the islands forming the five archipelagos of Macaronesia are all of volcanic origin, that their ages range from 0.27 Ma (Pico Island, Azores archipelago) to 29.5 Ma (Selvagens Islands) (Freitas et al., 2019), and that they have never been connected to any continent.
A few years later, the Catalogue des plantes du Maroc (Jahandiez & Maire, 1931, vol. 1, p. XI) presented a map of the geographical divisions of Morocco that included a Moroccan Macaronesian sector. The authors indicated that the map was based on the note by Maire and Emberger (1928), which provided an overview of phytogeographical knowledge of Morocco at the time. The document highlighted, along the Atlantic coastline, a Moroccan Macaronesian sector extending from Cape Cantin (now Cape Beddouza, north of Safi) to Agadir, justified by the relatively high proportion of Canary Island plants in its flora. Maire and Emberger (loc. cit., p. 284) stated that this Moroccan Macaronesian sector was, for the phytogeographer, inseparable from the Canary Islands. The Sous, characterized by Argania and Ziziphus savanna, corresponded, according to these authors, to the south-western steppe sector.
In 1934, at a congress in Rabat, Emberger, seeking to summarize floristic knowledge of Morocco, proposed dividing the country into six floral domains. He recognized only along the Atlantic coast a Morrocan-Macaronesian sector, characterized by a list of Canary species borrowed from Braun-Blanquet and Maire (1924). In contrast, the Sous was placed within a Saharo-Mauritanian domain, characterized by a relatively high contingent of tropical species or species related to tropical types (including Argania, Acacia gummifera, and cactiform euphorbias).
In a 1952 note, Sauvage recalled the existence along the Moroccan Atlantic coast of a zone referred to by phytogeographers as a Macaronesian enclave. Seventeen endemic taxa common to this coastal area and the Macaronesian islands, as well as twelve vicariants, can be recognized there (Peltier, 1973).
In a synthesis work, Monod (1957) proposed the major chorological divisions of Africa. within the Mediterranean region, and again only along the Atlantic coast, he recognized a Macaronesian domain.
In 1978, Quézel, in an analysis of the Mediterranean and Saharan flora of Morocco, also referred to a Moroccan Macaronesian sector, but on the Atlantic coast of Morocco, especially in the Sous Valley, whose essential physiognomic element is Argania spinosa. As thus defined, the Moroccan Macaronesian sector extended inland, reaching the western slopes of the High Atlas as well as the Anti-Atlas. For the first time, it was stated that the Moroccan Macaronesian sector ultimately corresponded to the distribution area of the Argan tree. Before 1978, all researchers had limited the Moroccan Macaronesian sector to a narrow coastal strip along the Atlantic coast, from the province of Tarfaya in the south to Safi in the north (Sauvage, 1952).
Sunding (1979), in an article devoted to the origin of the Macaronesian flora, considered that the Moroccan enclave formed part of Macaronesia* (fig. 1), and Kunkel (1980) adopted this view (in Del Arco Aguilar & Rodríguez Delgado, 2018, p. 51). The Moroccan Macaronesian sector also appears on the maps of Peyerimhoff (1946) and König & Bley (1988) (in Beyhl et al., 1995). On König & Bley’s map, it is labeled “vegetation rich in succulent plants.” Lobin (1982) and Biondi et al. (1994) likewise mention a Moroccan Macaronesian sector because of the large number of taxa shared with the Macaronesian islands.
The map of the biogeographical divisions of the Sous watershed (Peltier, 1982) was established according to the divisions proposed by Quézel (1978). However, it restricted the Moroccan Macaronesian sector to a narrow coastal and subcoastal strip about thirty kilometers wide, corresponding approximately to the cactiform euphorbia steppe, a unique steppe in North Africa shared with the insular Atlantic arid zones of the Canary Islands and Madeira (Le Houérou, 1995). The inland parts of the Sous watershed correspond to the North African Mediterranean domain (Quézel, 1978).
In 1982, Barbéro et al. analyzed the phytosociological structures of southwestern Morocco from Essaouira to the Drâa Valley along the coast, as well as in the Sous Valley. The order Acacio-Arganetalia was described, with two alliances (Acacion gummiferae and Senecio anteuphorbii–Arganion spinosae). From a biogeographical standpoint, the authors stated that the belonging of southwestern Morocco to the Mediterranean region, and not to the Macaronesian region, was evident (Barbéro et al., p. 314), and that the term Moroccan Macaronesian sector should be abandoned (ibid.).
In 1994, Benabid and Fennane summarized knowledge on Moroccan vegetation. They indicated that the Argan tree is an important feature of the Moroccan Macaronesian sector (p. 31). Consequently, the presence of this sector in Morocco was accepted. The authors noted that the potential communities of this sector belong, from a phytosociological standpoint, to the order Acacio-Arganetalia (Barbéro et al., 1982).
Gehu and Biondi (1996) described the psammophilous plant communities of dunes and sandy deposits along the southwestern Moroccan coast. Their originality lies in the high percentage of species shared between Morocco and the Canary Islands. In this publication, reference is made to a so-called Macaronesian Morocco, but the authors do not clearly take a position in favor of the presence of a Moroccan Macaronesian sector along the southwestern coasts.
Kim et al. (1996), in a study on the adaptive radiation of Sonchus subg. Dendrosonchus in the Canary Islands and concerning the delimitation of the Macaronesian distribution area, adopted Sunding’s (1979) viewpoint, reproducing in full figure 1 of his publication.
In 1999, Quézel and Médail carried out a detailed phytogeographical comparison of southwestern Morocco and the Canary Islands to determine whether the distribution area of the Argan tree in the infra- and thermo-Mediterranean arid and semi-arid belts should be included within a Macaronesian subregion. This analysis was based on comparisons of phytogeographical spectra, species life attributes (growth forms, succulence, dispersal), and homologous vegetation structures.
The conclusion was unequivocal: although the presence of succulent species and particular climatic conditions implies a close relationship with certain zones of the Canary Islands, southwestern Morocco must be regarded as a major refuge area for thermo-xerophilous species (Euphorbia, Caralluma, Aeonium, Dracaena , etc.) of the North African Mediterranean domain (Quézel & Médail, 2003, p. 64), and not at all as a Macaronesian enclave in Morocco. The main characteristics of this entity are the high percentages of Mediterranean native annuals and phanerophytes and the low level of adaptive radiation compared with the Canary Islands (Quézel & Médail, 1999).
In conclusion, the coastal and subcoastal zone of southwestern Morocco may be considered, from both physiognomic and historical perspectives, as an entity with Macaronesian affinities, at least when referring to the steppe of cactiform and pachycaulous euphorbias, which represents a unique type in North Africa. However, from a strictly phytogeographical and phytosociological standpoint, southwestern Morocco does not correspond at all to a Macaronesian enclave. Logically, the most recent synthesis on the world’s biogeographical regions places southwestern Morocco within the Mediterranean region (Loidi & Vynokurov, 2024).
The recent synthesis on Macaronesia (Fernández-Palacios et al., 2024) indicates that the integration of the African coastal enclave into the Macaronesian biogeographical region remains to be confirmed. This reservation is notably linked to the importance of back-colonization processes—dispersal of species from the islands to the continent—already documented in several plant lineages (Aeonium, Androcymbium, Convolvulus, Lotus, Euphorbia).
*Macaronesia is defined here in the classical sense, by comparing the flora and vegetation of the islands. The coherence and validity of Macaronesia as a biogeographical unit are called into question when one attempts to define it using marine groups with very different dispersal capacities (Freitas et al., 2019).
Références
Barbéro M., Benabid A., Quézel P., et al. 1982 - Contribution à l’étude des Acacio-Arganietalia du Maroc sud-occidental. Documents phytosociologiques, N.S. vol. VI, Camerino, 311-336.
Benabid A. & Fennane M. 1994 - Connaissances sur la végétation du Maroc : phytogéographie, phytosociologie et série de végétation. Lazaroa 14 : 21-97.
Beyhl F. E., Mies B. & Ohm P., 1995 - Macaronesia – A biogeographical puzzle. Bol. Mus. Mun. Funchal, Sup. N° 4 : 107-113.
Biondi, E., Allegrezza, M., Taffetani, F. & Wildpret De La Torre, W. 1994 - La vegetazione delle coste basse sabbiose delle isole di Fuerteventura e Lanzarote (Isole Canarie, Spagna). Fitosociologia 27: 107–121.
Braun-Blanquet J. et Maire R., 1924 - Etudes sur la végétation et la flore marocaines. Comptes-rendus des herborisations de la Société Botanique de France, session du Maroc, 1921. Mém. Soc. sc. nat. Maroc, 8 (1 partie), 244 p., 1 carte et 10 pl. h. t.Del Arco Aguilar M.J. & Rodriguez Delgado O., 2018 - Vegetation of the Canary islands. Plant and Vegetation, 16, Springer, 429 p.
Emberger L. 1934 - La végétation et la flore du Maroc. Aperçu général. In La science au Maroc. Casablanca, Impr. réunies, 169-180, 1 carte.
Fernandez-Palacios J. M. et al., 2024 - In defence of the entity of Macaronesia as a biogeographical region. Biological Reviews 99, 2060–2081, doi: 10.1111/brv.13112.
Freitas R., Romeiras M., Silva L. et al. 2019 - Restructuring of the ‘Macaronesia’ biogeographic unit: A marine multi-taxon biogeographical approach. Sci Rep 9, 15792 (2019). https://doi.org/10.1038/s41598-019-51786-6
Gehu J.M. & Biondi E. 1996 - Apport à la connaissance de la végétation du littoral marocain sud-occidental. Les communautés végétales psemmophiles des dunes et placages sableux du maroc macaronésien. Bull. Soc. Bot. Centre-ouest, nlle sér., 27 : 179-214.
Jahandiez E. & Maire R., 1931 - Catalogue des plantes du Maroc (Spermatophytes et Ptéridophytes. Tome premier : Ptéridophytes, Gymnospermes et Monocotylédones. Alger, Minerva, XL et 159 p.
Kim, S. C., Crawford, D. J., Francisco-Ortega, J. & Santos-Guerra, A. 1996 - A common origin for woody Sonchus and five related genera in the Macaronesian islands: Molecular evidence for extensive radiation. Proc. Natl. Acad. Sci. USA 93: 7743–7748.
Lobin W. 1982 - Untersuchung über Flora, Vegetation und biogeographische Beziehungen der Kapverdischen Inseln. Courier Forschungsinstitut Senckenberg 53, 1–112.
Loidi, J. & Vynokurov, D. 2024 - The biogeographical kingdoms and regions of the world. Mediterr. Bot. 45(2), e92333. https://doi.org/10.5209/mbot.92333
Maire R. & Emberger L., 1928 - Vue d’ensemble de nos connaissances phytogéographiques du Maroc : II. Les régions, domaines et secteurs. C. R. Ac. Sc., 186 : 282-284, 1 carte.
Médail F. & Quézel P, 1999- The phytogeographical significance of S.W. Marocco compared to the Canary Islands. Plant Ecology, 140 : 221-244.
Monod T., 1957 - Les grandes divisions chorologiques de l’Afrique. Rapport présenté à la réunion de spécialistes sur la phytogéographie (Yangambi, 29 juillet-8 août 1956). Londres, Conseil scientifique pour l’Afrique au Sud du Sahara, 24, 147 p. + 2 pl. h.-t.
Peltier J.P., 1973 – Endémiques macaronésiennes au Maroc. Inventaire bibliographique et problèmes taxonomiques. Proceeding of the I International Congress pro Flora Macaronesica. Monographiae Biologicae canarienses, Las Palmas, 4, 134-142.
Peltier J.P., 1982 -La végétation du bassin versant de l’oued Sous (Maroc). Thèse de Doctorat d’état, Université de Grenoble 1, Grenoble, 201 p + annexes.
Quézel P., 1978 - Analysis of the flora of the mediterranean and saharan Africa. Annals of the Missouri Botanical Garden, 65 : 479-534.
Quézel P., Médail F., 2003 – Écologie et biogéographie des forêts du bassin méditerranéen. Paris, Elsevier, Collection « Environnement », 573 p.
Sauvage Ch., 1952 - La végétation du littoral atlantique marocain. Bull. sc. océan. Études côtes du Maroc, 1 (série 2) : 3-10.
Sunding P. 1979 - Origins of the Macaronesian flora : 13–40, In Bramwell D. (Ed.), Plants and Islands. Academic Press, London.
Posted by Jean-Paul Peltier.
Recent floristic surveys conducted in various regions of Morocco have revealed three new records of non-native vascular plants of the genus Solanum, namely, S. abutiloides Bitter & Lillo, S. bonariense L., and S. nitidibaccatum Bitter. The occurrence of these alien species in Morocco is documented here for the first time. For each species, information on its national habitat and distribution are given. Moreover, the distinguishing morphological features of these three species are compared with the most similar species (including Moroccan Solanum species). The voucher specimen are deposited in the National Herbarium of Morocco (RAB), at the Scientific Institute of Rabat.
Réf. : Khamar H, Dallahi Y, & Homrani Bakali A. 2024. New records of three alien Solanum species in Morocco. Check List 20 (2): 544–552. https://doi.org/10.15560/20.2.544.
Posted by Jean-Paul Peltier.
The presence of the xenophyte plant Maireana brevifolia is reported for the first time in Morocco. The species is native to Australia and is currently colonizing a disturbed saline oasis in Skoura, province of Ouarzazate, though it might likely occur elsewhere in similar habitats.
A brief illustrated description and precise geographical Moroccan location of Maireana brevifolia are presented. The voucher specimen is deposited in the National Herbarium (RAB) of Morocco, at the Scientific Institute of Rabat.
Réf. : Giardi, L. & Homrani Bakali, H. 2023. Maireana brevifolia (Chenopodiaceae), an Australian xenophyte established recently in southeastern Morocco. Collectanea Botanica 42: e009. https://doi.org/10.3989/collectbot.2023.v42.009.
Posted by Jean-Paul Peltier.
Selon les phytosociologues, la steppe ligneuse basse à armoise blanche des hauts plateaux de l’Anti-Atlas occidental (Peltier, 1982) appartient à la classe des Lygeo- Stipetea tenacissimae Rivas-Mart. 1978 et à l’ordre des Lygeo sparti- Stipetalia tenacissimae Br-Bl et O. de Bolòs 1958* L’ordre est défini par Lygeum spartum, Stipellula parviflora (= Stipa parviflora), Stipa barbata et se localise en bioclimat aride et semi-aride et à l’étage mésoméditerranéen.
Une alliance nouvelle vient d’être déduite des données inédites de ma thèse (Peltier, 1982). Il s’agit du Launaea laniferae-Lygeion sparti Marcenò, Guarino, Mucina, Biurrun, Deil, Shaltout, Finckh, Font & Loidi 2019 lié aux dépôts argileux et limoneux, au pied des affleurements précambriens, qui possèdent de nombreuses colonies de Sparte, favorisées, du fait de la faible pente, par un bilan hydrique plus favorable (Marcenò et al., 2019). Cette nouvelle alliance est caractérisé par la dominance de Lygeum spartum, Carlina hispanica subsp. hispanica (= Carlina corymbosa auct.), Chamaerops humilis, Convolvulus trabutianus, et par la présence fidèle d'Erodium jahandiezianum (endémique locale), Launaea lanifera et Leysera leyseroides (Marcenò, et al., 2019).
La liste des caractéristiques est déduite des 15 relevés qui ont servi à définir l’alliance ; 9 sont extraits du tableau 19 de mon travail de thèse et correspondent à l’association à armoise blanche et Erodium jahandiezianum (Peltier, 1982).
L’association n’ayant jamais était publié, le Code International de Nomenclature Phytosociologique (ICPN, art. 1) impose de la rebaptiser. Ainsi est créé, (Marcenò, et al., 2019) le Convolvulo trabutiani-Lygeetum sparti Marcenò, Guarino, Mucina, Biurrun, Deil, Shaltout, Finckh, Font & Loidi 2019, avec comme holotype de l’association le relevé 1129, tableau 19 (Peltier, 1982).
Le Convolvulo trabutiani-Lygeetum sparti représente l’association holotype de l’alliance et l’association à armoise blanche et Erodium jahandiezianum qui est un nomen ineditum est obligatoirement mise en synonymie.
Les autres associations décrites des hauts plateaux anti-atlasiques sont différentes sur le plan écologique et floristique des peuplements dominés par Lygeum spartum (Peltier, 1982). Il n’est pas possible de les rattacher à l’une des deux autres alliances - Noaeo mucronatae-Lygeion sparti Marcenò, Guarino, Mucina, Biurrun, Deil, Shaltout, Finckh, Font & Loidi 2019 et Launaeo angustifoliae-Lygeion sparti Le Houérou 1969 – reconnues jusqu’à ce jour dans l’ordre des Lygeo-Stipetalia tenacissimae Br-Bl et O. de Bolos 1958, des recherches complémentaires sont nécessaires.
*cette ordre porte le nom de Stipellulo parviflorae- Lygeetalia sparti De Foucault & Noble, si on décide de ne pas prendre en compte les thérophytes dans les relevés (Foucault & Noble, 2023).
Références citées
Braun-Blanquet J. & de Bolòs O., 1957 (publié 1958) - Les groupements végétaux du bassin moyen de l’Ebre et leur dynamisme. Anales de la Estacion experimental Aula Dei 5 (1-4) : 1-266.
Foucault B. (de) & Noble V., 2019. Contribution à une synthèse des Lygeo sparti-Macrochloetea tenacissimae. Société botanique d’Occitanie. Carnets botaniques, article n° 149. 30 juillet 2023. DOI : https://doi.org/10.34971/V632-0572.
Le Houérou H.-N., 1969. La végétation de la Tunisie steppique avec références aux végétations analogues de l'Algérie de la Libye et du Maroc. Annales de l’Institut national de recherches agronomiques de Tunisie 42 : 1-624.
Marcenò C., Guarino R., Mucina L., Biurrun I., Deil U., Shaltout K., Finckh M., Font X. & Loidi J., 2019. A formal classification of the Lygeum spartum vegetation of the Mediterranean Region. Applied Vegetation Science 0: 1-16, https://doi.org/10.1111/avsc.12456.
Peltier J.P., 1982 - La végétation du bassin versant de l’Oued Souss (Maroc). Thèse Doctorat d’Etat, Univ. Scientifique et Médicale de Grenoble, Grenoble, 201 p.
Rivas-Martínez S., 1978 - Sur la syntaxonomie des pelouses thérophytiques de l'Europe occidentale. Colloques phytosociologiques VI, La végétation des pelouses sèches à thérophytes : 55-69.
Posted by Jean-Paul Peltier.
Phlomis lychnitis is here recorded for the first time within the African continent. So far, known only from Morocco in the Oriental High Atlas. Description of the species as well as first data about its ecology in Morocco together with geographical distribution and diagnostic features with the morphologically closest taxon sharing yellow-colored flowers are given. Photographic illustrations and an updated key to the Phlomis species in Morocco are also provided.
Réf. Homrani Bakali, H. & Chatelain, C. 2023 - Phlomis lychnitis (Lamiaceae), an addition to the flora of Africa from Morocco. Collectanea Botanica 42: e004. https://doi.org/10.3989/collectbot.2023.v42.004
Posted by Jean-Paul Peltier.
Last modified on Wednesday, March 18, 2026 at 15h30.