Additional species of Agave (Agavoideae/Agavaceae, Asparagaceae sensu lat.) introduced and naturalising in Tunisia and North Africa Authors: Mokni, Ridha El, and Verloove, Filip Source: Bradleya, 2021(39) : 221-235 Published By: British Cactus and Succulent Society URL: https://doi.org/10.25223/brad.n39.2021.a23 BioOne Complete (complete.BioOne.org) is a full-text database of 200 subscribed and open-access titles in the biological, ecological, and environmental sciences published by nonprofit societies, associations, museums, institutions, and presses. Your use of this PDF, the BioOne Complete website, and all posted and associated content indicates your acceptance of BioOne’s Terms of Use, available at www.bioone.org/terms-of-use. Usage of BioOne Complete content is strictly limited to personal, educational, and non - commercial use. Commercial inquiries or rights and permissions requests should be directed to the individual publisher as copyright holder. BioOne sees sustainable scholarly publishing as an inherently collaborative enterprise connecting authors, nonprofit publishers, academic institutions, research libraries, and research funders in the common goal of maximizing access to critical research. Downloaded From: https://bioone.org/journals/Bradleya on 18 Jun 2021 Terms of Use: https://bioone.org/terms-of-use Access provided by Botanic Garden Meise Bradleya 39/2021 pages 221–235 Additional species of Agave (Agavoideae /Agavaceae, Asparagaceae sensu lat.) introduced and naturalising in Tunisia and North Africa Ridha El Mokni1,2,3 and Filip Verloove4 1. University of Monastir, Laboratory of Botany, Cryptogamy and Plant Biology, Faculty of Pharmacy of Monastir, Avenue Avicenna, 5000-Monastir, Tunisia. (email: [email protected]) 2.University of Jendouba, Laboratory of Silvo-Pastoral Resources, Silvo-Pastoral Institute of Tabarka, B P. 345, 8110-Tabarka, Tunisia. 3. University of Carthage, Laboratory of Forest Ecology, National Research Institute of Rural Engi- neering, Water and Forests, Ariana 2080, Tunisia. 4. Meise Botanic Garden, Nieuwelaan 38, B-1860 Meise, Belgium. (email: filip.verloove@botanicgar- denmeise.be) Summary: Recent fieldwork in Tunisia yielded Introduction several new records of non-native species of the Non-native plants, known also as exotic, intro- genus Agave. Agave angustifolia var. marginata, A. duced, alien, or non-indigenous, are those taxa fourcroydes and A. sisalana are locally naturalised whose presence in a given area is due to inten- and reported for the first time from the country. To tional or unintentional human involvement, or our knowledge, naturalised populations of these which have arrived there without the help of peo- three taxa were also unknown elsewhere in the ple from an area in which they are native (Pyšek et Maghreb and North Africa. We also draw attention al., 2004). Such species are widely recognised as to A. attenuata subsp. attenuata, a widely grown a significant component of human-caused global ornamental that is expected to become naturalised environmental change, resulting often in a sig- in the near future. Updated nomenclature, brief nificant loss in biological diversity and function descriptions, as well as general and national dis- of invaded communities and ecosystems (Mooney tributions are provided for each of the naturalised & Hobbs, 2000; Mack et al., 2000; Pimentel et al., Agaves. A key to all the species, subspecies, and 2001). varieties of Agave that occur in Tunisia is present- In North Africa, published information re- ed, and all the taxa are illustrated. garding the naturalisation and expansion of alien plants has a substantial history. About 340 alien Zusammenfassung: Jüngste Feldforschungen in vascular plant species have been recorded so Tunesien ergaben mehrere interessante neue far (i.e. c. 5% of the flora) (cf. Vilà et al., 1999). Nachweise nicht-heimischer Arten der Gattung From the viewpoint of the geographic origin of Agave. A. angustifolia var. marginata, A. fourcroy- the alien invading species, almost 50% come from des und A. sisalana sind lokal eingebürgert und the New World. Most of the expanding species werden erstmals für dieses Land dokumentiert. are ornamentals, originally deliberately intro- Nach unserem Kenntnisstand waren eingebürgerte duced by humans (Le Floc’h et al., 1990; Vilà et Populationen dieser drei Taxa auch anderswo al., 1999). In the past two decades, the knowledge im Maghreb und in Nordafrika unbekannt. Wir of the non-native flora of Tunisia and North Af- machen auch auf A. attenuata subsp. attenuata rica significantly increased (see e.g. El Mokni & El aufmerksam, eine mehr oder weniger weit verbre- Aouni, 2011a,b, 2012, 2013; El Mokni & Domina, itete Zierpflanze, von der zu erwarten ist, dass sie 2018, 2020; El Mokni & Verloove, 2019a, 2019b; in naher Zukunft eingebürgert sein wird. Für jedes El Mokni et al., 2012, 2016; El Mokni & Iamonico, Taxon der eingebürgerten Agaven werden die ak- 2018a, 2019; El Mokni, 2018, 2019; Iamonico & El tualisierte Nomenklatur, kurze Beschreibungen Mokni, 2016). However, information about alien sowie die allgemeine und nationale Verbreitung succulent plants is mostly recent and still scarce präsentiert. Ein Bestimmungsschlüssel zu allen in (see e.g. El Mokni & Iamonico, 2018a; El Mokni & Tunesien vorkommenden Arten, Unterarten und Sáez, 2019; El Mokni et al., 2018, 2019a, 2019b, Sorten der Agave wird vorgestellt und alle Taxa 2020). North Africa includes Morocco, the North- werden abgebildet. ern part of Mauritania, the Northern part of Mali, Bradleya 39/2021 221 Downloaded From: https://bioone.org/journals/Bradleya on 18 Jun 2021 Terms of Use: https://bioone.org/terms-of-use Access provided by Botanic Garden Meise Tibesti Mountains of Chad, Algeria, Tunisia, Lib- In this paper all taxa (subgenera, sections, species, ya and Egypt with Canary and Madeira Islands, and infraspecific taxa) are arranged alphabetical- whereas Maghrebian countries are restricted to ly. Nomenclature of the taxa presented is mostly Mauritania, Morocco, Algeria, Tunisia and Libya in accordance with recent phylogenetic classifica- (cf. Dobignard & Chatelain, 2010). tions of the family Agavaceae (see e.g. Thiede et Agave is the largest genus in the family Aga- al., 2019; Verloove et al., 2019). Newly reported vaceae. As presently circumscribed, this family taxa are indicated in bold in the key. is entirely confined to New World temperate and tropical areas, with eight genera and more than Results 276 named taxa (see e.g. Verhoek, 1998; Smith & Agavaceae Dumort., Anal. Fam. Pl. 57, 58. 1829. Figueiredo, 2014). The genus, comprising species nom. cons. Cronquist: 1217 (1981). of rosulate and succulent-leaved perennials, is na- Agave L., Sp. Pl. 1: 323. 1753. tive to the southern parts of the United States of Plants perennial and monocarpic. Stems very America, Mexico, Central America and the north- short or indistinct. Leaves in a basal rosette, large, ern parts of South America (Gentry, 1982; Mab- stout, leathery-fleshy or somewhat woody, con- berley, 1997). A number of species has, since the taining many fibers, margin usually spiny, rarely early 1860s, been introduced in Africa and even- entire, apex tipped with a spine. Flowering stems tually became established, among which two are branched or simple, tall, stout. Inflorescence ter- widely distributed: A. americana L. var. ameri- minal, a spike or panicle, mostly very large. Peri- cana and A. sisalana Perrine (Smith & Mössmer, anth tube short; lobes narrow, subequal. Stamens 1996). Both are currently included in catalogues inserted at throat or in tube of perianth; filament of problem plants in southern Africa (Wells et al., filiform, usually longer than perianth; anther ver- 1986; Henderson, 1995). satile. Ovary with many ovules. Style slender; Agave has been traditionally divided into two stigma 3-lobed. Fruit a capsule, oblong, 3-valved, subgenera (Berger, 1921; Gentry, 1982), defined on loculicidal. Seeds numerous, black, thin, flat- the basis of the inflorescence type: A. subg. Littaea tened. (Tagl.) Baker, which has an unbranched spike or Within Agavaceae subfam. Agavoideae five racemose inflorescence and contains about fifty- species and two varieties are here reported from three species with a more restricted distribution, Tunisia. For three of them, Agave angustifolia Haw. primarily in Mexico, and A. subg. Agave, whose var. marginata Hort. ex Gentry and A. fourcroydes species possess branched (paniculate) inflores- Lem., naturalised populations are reported for cences, i.e. large umbelliferous aggregates of flow- the first time in the Maghreb and North Africa. ers (Gentry, 1982), and includes c. 102 species. Agave attenuata Salm-Dyck subsp. attenuata (the The present contribution aims at improving only taxon in A. subg. Littaea) is also included. the gaps in the knowledge on taxa of the alien ge- Its escape from cultivation is expected but not yet nus Agave L. that are either new to the Tunisian or observed in Tunisia. An updated key to all species Maghrebian allochthonous flora in North Africa. and varieties of Agave occurring in Tunisia is pro- vided. Material and Methods Floristic field investigations in Central and North- ern Tunisia (North Africa), mostly between 2010 Agave subg. Agave A. sect. Agave and 2020, have revealed new populations of Agave species. Some taxa, observed frequently in Agave americana L. Sp. Pl.: 323. 1753. small colonies, were not previously reported from = Aloe americana (L.) Crantz, Inst. Rei Herb. 1: Tunisia or North