Cynosurus peltieri Maire (1931: 155

Mokni, Ridha El & Verloove, Filip, 2022, Cynosurus peltieri (Pooideae, Poaceae), a poorly known species endemic to the Algerian-Tunisian terrestrial flora: further insights on its occurrence, IUCN Red List assessment, and lectotypification, Phytotaxa 538 (4), pp. 292-300 : 294-298

Cynosurus peltieri Maire (1931: 155 , 321)

Type: — ALGERIA. Massif de l’Akfadou , dans le Quercetum fagineae et le Quercetum afares entre Tala Ouzar et Tala Kitan, grès, 1000– 1300 m, 15.06.1931, R. Maire s.n. (lectotype designated here MPU barcode MPU-002706, image available at: http://mediaphoto. mnhn.fr/media/1442358244293KHY9RGa9b5Ygs2j3; isolectotypes BC barcode BC-139421, image available at: https://api.gbif. org/v1/image/unsafe/http%3A%2F%2Fwww.ibb.csic.es%2Fherbari%2FJPEG%2FBC139421.jpg, P barcode MNHN-P-P00083491, image available at: https://science.mnhn.fr/institution/mnhn/collection/p/item/p00083491?listIndex=1&listCount=11) .

Morphological description ( Fig. 1 ):—Green grass, perennial, rhizomes ± long creeping, producing loosely caespitose innovations and flowering culms. Culms 30–70 cm, striated, glabrous and smooth. Leaf-sheaths rounded on the back, striated, glabrous and smooth, appressed, ligule short (<1 mm), truncated. Leaf-blades flat, not rigid, attenuated in a short ± acute callus point, up to 30 cm × 2.5 mm, striated, glabrous and smooth on both surfaces, with smooth and glabrous margins. Panicle long stalked, 4–16 × 0.5–1.2 cm, linear to linear-lanceolate, ± loose, distinctly lobed, unilateral, spiciform, lower branches very often elongated and spaced, rather loosely branched, pubescent-scabrous; axis angular, little flexuous, little scabrous. Spikelets greenish, up to 6 mm with very few sterile spikelets. Sterile spikelets well-developed with undifferentiated glumes and lemmas, tight, linear, laterally compressed, rather long attenuated in one ridge of 1.00– 1.25 mm, few (4–7), exserted from glumes, 4–6 mm long, 1-awned with 1.0– 2.5 mm long awn and with scabrous unwinged keel. Fertile spikelets comprising 1–2 fertile florets; flowers articulated on a smooth rhachilla; rhachilla extended in above upper flower. Glumes persistent, slightly unequal, linear lanceolate; lower glume c. 4–6 mm long, equal to length of upper glume, membranous, 1-keeled, 1-veined, primary vein scaberulous, lateral veins absent, apex acuminate, 1-awned, awn 0.5–1.0 mm long; upper glume c. 4–6 mm long, 0.9–1.1 times length of adjacent fertile lemma, membranous; 1-keeled; 1-veined, lateral veins absent, apex acuminate, 1-awned, awn c. 0.5–1.0 mm long. Fertile lemma 5-veined, ovate-lanceolate, a little scabrous abaxially in upper half, rather abruptly attenuated at top to a short awn (c. 1 mm), c. 5 mm long (awn included). Palea roughly equal to lemma, lanceolate, obtusius and bimucronate at top, with 2 closely spaced keels scaberulous in upper part. Lodicules 2, slightly brownish, lanceolate-sickle-shaped, subacute, c. 0.5–0.6 mm, greater than ovary. Anthers 3, linear, yellow, c. 2.5 mm. Ovary glabrous, with 2 apical styles briefly naked. Caryopsis with adherent pericarp (cf. Maire 1955, Cuénod et al. 1954, Quézel & Santa 1962, POWO 2022b).

Phenology:—Flowering time is June to July; fruiting time is August to September.

Chromosome number:—2n =? (unknown).

Diagnostic characters:— Cynosurus peltieri is very close to C. polybracteatus [= C. cristatus subsp. polybracteatus ( Poiret 1789: 97) Trabut (1895: 190) , Fig. 2 ]. Both have unilateral linear panicles (up to 16 cm long) and a very short, truncated ligule. In contrast, C. peltieri is distinguished from C. polybracteatus by its perennial habit (vs annual), its clearly lobed, relatively loose panicle ( Fig. 1B ), with lower branches often elongated and distant (vs dense panicle, indistinctly lobed, with very short branches, Figs. 2B, 2C ). Lemmas of sterile spikelets in C. peltieri are long-attenuate, with a long awn (1.00– 1.25 mm) whereas in C. polybracteatus , sterile spikelets have briefly mucronate lemmas. A further reliable character for separating C. peltieri from C. polybracteatus is fertile spikelets with 1 or 2 florets, with awned glumes and lemmas (vs 3–5 florets, with mucronate glumes and muticous lemmas in C. polybracteatus ) (cf. Maire 1955; Cuénod et al. 1954, Quézel & Santa 1962).

Distribution:— Cynosurus peltieri is indigenous to Algeria and Tunisia in North Africa and no records for the species appear to have been published outside its terra typica since its discovery. The plant is regarded to be rare where it occurs in shady, altitudinal (800– 1.500 m a.s.l.) and cool humid(-perhumid) regions of mixed oak forests of the Akfadou and Aïn-Draham mountains ( Maire 1955, Cuénod et al. 1954, Quézel & Santa 1962). Thus, we here reported additional localities besides that reported by Cosson in the 19 th century (cf. Cuénod et al. 1954).

Habitats and co-associated flowering species:— Cynosurus peltieri is part of the shady herbaceous flora of the altitudinal Kabylian and Kroumirian oak forests. In Tunisia, Cynosurus peltieri is a main component of the Cynosuro peltierii -Quercetum afaredis Laribi ex El Mokni 2022 association, together with a rich geophytic herbaceous floristic component of the mixed oak forest of Aîn Zana where it reaches its greatest abundance with Quercus afares ( Laribi 2000, El Mokni 2022b). Outside Aîn Zana oak forests, Cynosurus peltieri shows sporadic occurrences usually on humified pseudogley soils lying on the numidian sandstones where it is abundant, especially in years with high rainfall.

In these habitats, Cynosurus peltieri is mainly associated with many acidic species among some North African, Algerian-Tunisian, and Tunisian endemics: Ajuga reptans L., Agrimonia eupatoria L., Cyclamen africanum Boiss. & Reut. , Eryngium tricuspidatum subsp. bovei (Boiss.) Batt. , Galactites mutabilis , Galium tunetanum , Hyacinthoides aristidis , H. kroumiriensis El Mokni, Domina, Sebei & El Aouni , Lapsana communis subsp. macrocarpa (Coss.) Nyman , Luzula forsteri (Sm.) DC. , Ophrys tenthredinifera subsp. ficalhoana , Phlomis bovei de Noé subsp. bovei , Plagius maghrebinus Vogt & Greuter , Platanthera bifolia subsp. kuenkelei , Sanicula europaea , Scutellaria columnae All. , and Teucrium atratum (cf. El Mokni 2022b).

Additional specimens seen:— ALGERIA (historical records). Kabylie, chênaies de l’Akfadou, près de Tala-Ouzar et Tala-Kitan, sur grès éocène, 1000–1300 mètres, 15 Juin 1931, Dr. R. Maire, 2586 (BC-139422, MPU-064905, MPU-076129, P-02636068, P-03371017). In quercetis moatium Akfadou Kabyliae, solo arenaceo, 1400 m, 20.06.1937, Dr. R. Maire s.n. (MPU-064908). A yakouren, clairières ou Quercetum suberis, fin juin 45, Dr. R. Maire s.n. (MPU-064906).

TUNISIA (historical records). Ain Draham ( Khroumirie ), 7.7.1883, E. Cosson s.n. (MPU-064907) . TUNISIA (new records). Jendouba, Aîn-Zana , within oak forests, about 577 m a.s.l., 31 July 2018, El Mokni s.n. (Herb. El Mokni); ibidem, 18 June 2019, El Mokni s.n. (Herb. El Mokni); ibidem, 16 June 2020, El Mokni s.n. (Herb. El Mokni); El Ghorra, within oak forests, about 1051 m a.s.l., 26 June 2020, El Mokni s.n. (Herb. El Mokni); El Feidja, within oak forests, about 1079 m a.s.l., 24 June 2020, El Mokni s.n. (Herb. El Mokni); Fernana-Béni Mtir, within oak forests, about 819 m a.s.l., 01 July 2009, El Mokni s.n. (Herb. El Mokni); Aîn Draham-Oued Zéen, ibidem, within oak forests, about 768 m a.s.l., 03 August 2018, El Mokni s.n. (Herb. El Mokni); Béni-Mtir/Aîn Sallem, within oak forests, about 925 m a.s.l., 15.6.2020, El Mokni s.n. (Herb. El Mokni); Aîn Draham/Mridj, within oak forests, about 709 m a.s.l., 03 July 2012, El Mokni s.n. (Herb. El Mokni) .

Conservation status

In total, only nine localities of Cynosurus peltieri are currently known in North Africa ( Algeria and Tunisia), historical as well as recent. All populations are scattered with a limited number of mature individuals, which does not exceed 20 per population, as far as Tunisia is concerned. Their occurrence is restricted to oak forests of the Kroumirian mountains (NW of Tunisia) and Kabylian mountains (NE of Algeria) that are dominated by Mirbeck oak with cork and afares oaks. Based on the Threats Classification Scheme by IUCN (2021), we can highlight the following:

2. Agriculture (2.3 Livestock farming, 2.3.1 Nomadic grazing): continuous overgrazing, in Tunisia especially by large numbers of goats, and in Algeria with the intense frequency of cattle ( Meddour 1993, Laribi 2000), constitutes the most obvious threat to these communities and to the native biodiversity that they shelter in such ecosystems. Continuous overgrazing will result in retrogression, stimulate growth and extension of weeds and plants of the pastoral rangelands with the decrease or even loss of native and endemic diversity;

7. Natural system modifications (7.1 Fire, 7.1.1 Increase in fire frequency/intensity): the increase of frequency of fires during mainly the previous decade facilitates the fragmentation, even the irreversible destruction of habitats, and disrupts important processes such as gene flow; (7.3 Other ecosystem modifications): the improper, excessive, and continuous collection of litter under oak trees by nurserymen can destroy any pedological process that favour the formation of a humus soil, which is suitable for the conservation of such biodiversity;

12. Other options (12.1 Other threats): the lack of efficient strategies by governments for conservation of such fragile habitats, for rehabilating burnt areas with indigenous taxa, and to help the high resilience of species populations against fire damages; this is amplified by the negative impact (mainly during the previous decade) of a very high attendance of uninformed hikers not keeping to pathways, and heavy trampling during the beatings of wild boars.

The nine reported North African populations in nine sites (historical and new records), show an Area of Occupancy (AOO) of only 32 km 2 (<< 500 km 2) and an Extend of Occurrence (EOO) of 5.956 km 2. Given its discontinuous distribution and a decline in the quality of habitats (fragmentation, overgrazing, and habitat modification due to continuous illegal and excessive logging and litter transfer), Cynosurus peltieri can be assessed as Endangered (EN) in North Africa, according to the International Union for Conservation of Nature ( IUCN 2021) criteria [B2b(i,ii,iii,iv)c(i,ii,iii)+C1+C2a(i,ii)b+D1].

Conservation measures:—Despite great efforts made during more than two decades in monitoring of oak forests of Kroumiria and their high biodiversity heritage, a lot still needs to be done. More conservation measures should be urgently and more seriously undertaken, and conservation strategies in the shady oaks forests of Kroumiria should aim at: in situ, to put an end to the excessive and massive overgrazing in areas with a very rare and endangered endemic flora, and legally declare these oak forests as a no-grazing area in order to save what remains of the extant populations, and to monitor their status and their habitat quality.

Figures

FIGURE 1. Cynosurus peltieri in its typical habitat in Kroumirian oak forests. A. Habit of the plant. B. Detail of its unilateral and linear, clearly lobed panicle.All photographs were taken by Ridha El Mokni in Aîn Zana-Aîn Draham (Jendouba, NW of Tunisia, North Africa), 16 June 2020.

FIGURE 2. Cynosurus polybracteatus in its habitat in Kroumirian area. A. Habit of the plant. B–C. Details of its unilateral and linear, indistinctly lobed panicle, with very short branches.All photographs were taken by Ridha El Mokni in Tabarka (Jendouba, NW of Tunisia, North Africa), 14 May 2013 and 3 May 2017.