Zahora ait-atta Lemmel & M.Koch, gen. et, 2019

Koch, Marcus A. & Lemmel, Claude, 2019, Zahora, a new monotypic genus from tribe Brassiceae (Brassicaceae) endemic to the Moroccan Sahara, PhytoKeys 135, pp. 119-131 : 119

Zahora ait-atta Lemmel & M.Koch, gen. et sp. nov.

Type.

Morocco. Meknés-Tafilalet/Drâa-Tafilalet: Border region with Algeria. Near Errachidia. Oued Bou-Ibourine, " Zizaou n´oudad ", gps 31.4114, -3.7220, 900 m a.s.l., 11th March 2019, C. Lemmel s.n. (Holotype, HEID 505689; Isotype, G00394714, Conservatoire et jardin botanique de Genève; Paratype, HEID 505749, 505750, ex. cult. Botanical Garden Heidelberg 2019). Figure 1 .

Description.

Herbs, woody at base, monocarpic, simple trichomes; rhizome fleshy, 2-3 cm in diam. Stems 80-140(-180) cm tall, robust, up to 1.4 cm in diam, erect, simple at base, often alternately branched in lower part. Basal leaves rosulate, fleshy; leaves lyrate, distal lobecordate, (10-)15-25(-40) cm, margin entire to distantly dentate, numerous simple trichomes on lower surface mostly along veins, upper side loosely covered with simple trichomes; cauline leaves similar but apex obtuse to weakly subacute, 10-15 × 5-7 cm. Raceme ebracteate, elongating in fruit, 40-100 cm; often branched. Sepals erect, saccate ca. 8 mm long, with few simple trichomes; petals pale-yellow,1.5-1.7 cm long, 6-7 mm wide, petal claw 8 mm long, obtuse at apex, glabrous. Filaments tetradynamous, ca. 9 mm long; nectar glands 4, rounded, elateral pair larger. Stigma entire. Infructescence with up to 100(-200) siliques, (30-)40-45(-48) mm, petiolate (9-11 mm). Fruits heteroarthrocarpic with a distal indehiscent balloon-like structure with two viable seeds (3.5-5 × 6-8 mm); proximal part dehiscent, terete (30-45 mm); 20-40 ovules; septum complete. Seeds biseriate, mucilaginous, 1.3-1.4 × 1.4-1.5 mm.

Etymology.

Zahora means “flower” in Arabic, indicating the attractive and peculiar appearance of the plant. “Aït-atta” are a Berber tribal confederation of south eastern Morocco who locally know the plant under the name "Zizaou n’oudad» ( Barbary-sheep’s cabbage).

Distribution and habitat.

The species is a local endemic and was observed at the following and additional places at given dates. From these localities no additional vouchers have been collected, and to our knowledge the species has never been sampled before:

Begaa: [27th January 2015] - gps 30.9453, -3.8767; 680 m a.s.l.

Khamlia: [02nd February 2015] - gps 30.9895, -3.9863; 680 m a.s.l.

Oued-Bou-Ibourine: [09th March 2017] - gps 31.4146, -3.7537; 900 m a.s.l.

Oued-Bou-Ibourine: [04th April 2017] - gps 31.4062, -3.7353; 900 m a.s.l.

Oued-Bou-Ibourine: [02nd December 2017] - gps 31.4115, -3.7214; 900 m a.s.l.

Khamlia: [08th February 2018] - gps 30.9906, -3.9918; 680 m a.s.l.

Taous: [10th October 2018] - gps 30.9286, -3.9753; 680 m a.s.l.

Khamlia: [08th February 2019] - gps 30.99879, -3.9875; 680 m a.s.l.

Oued-Bou-Ibourine: [11th March 2019] - gps 31.4114, -3.7220; 900 m a.s.l.

Oued-Bou-Ibourine: [11th March 2019] - gps 31.4127, -3.7419; 890 m a.s.l.

Begaa: [12th March 2019] - gps 30.9293, -3.9740; 680 m a.s.l.

Habitat.

All places are in sandy beds of oueds flowing from the base of the kreb (cliff) of the Hamada du Guir or the Bin el Korbine.

Phenology.

The species flowers in spring (February to March). Seeds germinate in late summer and autumn if soil moisture is sufficient and rosettes are formed persisting throughout the winter. After fruit stage seeds are dispersed and monocarpic plants are dying.

Ecology.

Greenhouse and pollination experiments showed that the species is largely self-compatible. At its natural stands the plant is annual and monocarpic. However, in cultivation the plant species can be kept growing when cutting frutescence. There are two different options of seed release, either directly into a local soil seed bank from the dehiscent part of fruit or via the distal indehiscent part carrying two seeds, which may allow distributing effectively with water in the wadi systems at rare and occasional events.

Provisional IUCN conservation assessment.

The extent of occurrence is less than 10,000 km2 and falls within the limits of “Vulnerable” (VU) category under criterion B1. Since populations are of small sizes and occur at unique habitat types only, we assign an IUCN conservation status of VU B1.

Figures

Figure 1. Zahora ait-atta in its natural environment. Border region with Algeria. Near Errachidia. Oued Bou-Ibourine - type locality a sandy habitat b flowering plant c rosette during winter d lyrate leaf from lower part of the plant e rosette starts building the inflorescence f ripening heteroarthrocarpic fruits g flowers and detailed view on sepals h siliques releasing seeds from dehiscent distal part of fruit. Images taken by C. Lemmel and Z. Attioui.