Diplotaxis kohlaanensis A. G. Miller & J. A. Nyberg 1994

Diplotaxis kohlaanensis A. G. Miller & J. A. Nyberg 1994 View in CoL

Materials

Type status: Other material. Occurrence: individualCount: 100; occurrenceID: 0DD55C97-CA41-5778-B3F7-F8CECAA94124; Taxon: scientificNameID: Diplotaxis kohlaeensis ; kingdom: Plantae; order: Brassicales ; family: Brassicaceae ; genus: Diplotaxis ; Location: continent: Africa; country: Ethiopia; locality: Simien Mountains ; verbatimElevation: 3900 m; verbatimLatitude: 13°15'20.17"N; verbatimLongitude: 2 38°10'9.31"E; Identification: identifiedBy: S. Cambria; dateIdentified: 23-12-2024 GoogleMaps

Description

Shrubby and compact chamaephyte, generally glabrous, with many stems arising from a woody rootstock. Flowering branches erect or ascending, 30–60 cm long. Leaves slightly fleshy, glaucous, all petiolate with a well-marked whitish mid-rib. The lower ones with ovate to oblong-ovate blade, 15–80 × 10–20 cm, obtuse apex and serrate margin with 4–6 pairs of teeth or sinuate to entire, rarely with few scattered hairs. Upper leaves smaller, 5–40 × 5–10 mm, provided with a shorter petiole. Racemose inflorescence, erect or ascending, with the flowers overtopping the buds. Flower pedicels 10–14 mm long, equal or shorter than to the petals. Calyx with four sepals, 5–6 mm long, generally 2.5–3 times shorter than the petals, externally hairy particularly along the mid-rib and near the base. Inner sepals 1.8-2.5 mm broad and saccate at base, the outer 1.5–2 mm broad, with non-saccate base and clearly hooded tip. Corolla with four petals, pale yellow, broadly obovate and narrowing below into a linear claw, 10–14 × 5-6 mm, with rounded tip. Androecium consisting of 6 stamens; the median 8–11 mm long, with prominent nectarial glands at the base; the lateral 6–7 mm; anthers 2–3 mm long. Gynoecium with cylindrical ovary, glabrous, shortly stipitate; stigma bilobed. Siliques erect or patent, linear to linear-oblong, flattened, 12–40 × 2.5–3.2 mm, with the seeds in two rows; beak seedless, 1.5–2 mm long; Seeds pale reddish to brown, flattened, 1–1.5 × 0.5 – l mm (Fig. 2 View Figure 2 , Fig. 3 View Figure 3 ).

Distribution

Based on the current knowledge, the species is localised in Ethiopia on the vertical, basaltic, north-facing cliffs of the Simien Mts. at an altitude ranging from 3,700 to 3,900 m a. s. l.

Ecology

The species was found on the escarpment below Mt. Inatye, which is characterised by chasmophytic vegetation rich in rare and phytogeographically relevant species, such as Aeonium leucoblepharum Webb ex A. Rich. , Arabis alpina L. subsp. alpina , Campanula edulis Forssk , Poa simensis Hochst. ex A. Rich. , Helichrysum citrispinum Delile var. citrispinum , Dianthus longiglumis Delile , Rosularia semiensis (J. Gay ex A. Rich.) H. Ohba , Asplenium aethiopicum (Burm. f.) Becherer and marginally also Primula verticillata Hochst. subsp. simensis (Hochst.) W. W. Sm. & Forrest [= Evotrochis simensis (Hochst.) Fırat & Lidén ].

Conservation

The population of D. kohlaanensis entirely falls within the Simien National Park, a protected area created in 1969, a period when 80 % of the Park was subjected to human exploitation through livestock grazing, cultivation and settlements ( Debonnet et al. 2006). Actually, this is still threatened by human activities, particularly grazing and logging ( Jacob et al. 2016), further aggravated by the recent war events which led to a severe reduction of the wooded areas due to coppicing and fires, as highlighted by Meaza et al. (2025) for other mountains of northern Ethiopia. For this reason, the Simien Mountain National Park has been listed as a World Heritage Site in Danger since 1997. Despite this, the vertical cliffs are poorly affected by human disturbance due to their inaccessibility and, therefore, they represent the best-preserved environments of this area. The population of D. kohlaanensis contains a very low number of individuals (roughly estimated in ca. 100 mature plants) that, even if not immediately threatened, at this stage, we do not know how the species would respond to global warning. By using the Geospatial Conservation Assessment Tool ( Bachman et al. 2011), the extent of occurrence (EOO) is calculated to be 0.028 km 2, while the area of occupancy (AOO) is 4 km 2. Following the IUCN Criteria at global and regional level ( IUCN 2001, IUCN 2003), with the estimated EOO less than 100 km 2, an AOO less than 10 km 2, the conservation status of D. kohlaanensis for Ethiopia has been classified as Endangered at regional level (EN reg: D) according to criterion D.

Biology

Flowering and fruiting during the dry season from November to March.