Ceropegia lodarensis (Lavranos) Bruyns var. rubrosticta (Plowes) Alharbi & Al-Qthanin, 2021

Alharbi, Samah A. & Al-Qthanin, Rahmah N., 2021, Taxonomic revision of Ceropegia sect. Huernia (Asclepiadoideae, Apocynaceae) in Saudi Arabia with three new combinations, PhytoKeys 174, pp. 47-80 : 47

4.3 Ceropegia lodarensis (Lavranos) Bruyns var. rubrosticta (Plowes) Alharbi & Al-Qthanin comb. nov. Figs 14 , 15 ; Map 6

Huernia rubrosticta ≡ Huernia rubrosticta Plowes, Asklepios 114: 11 (2012).

Type.

Saudi Arabia - Najran • I. S. Collenette 1482 (holotype: k! herb. material); Jabal Manfah , 24 km NE Najran; 17°36.9386'N, 44°12.3742'E; alt. 1700 m; 30 Apr 1979 .

Description.

Branches 30-60 mm long, stout; tubercles 5.5-6 mm long (including leaf-rudiment), 2-3 mm broad at base. Inflorescence bearing 6 flowers developing in gradual succession from short peduncle, flowers with faint unpleasant smell; pedicel 11 mm long, 2 mm thick, ascending holding flower facing upwards, tapering sometimes towards the point of flower attachment; sepals 9.5 mm long, 2 mm broad at base, attenuate. Corolla 32 mm diam., campanulate; outside smooth, cream-speckled with pale maroon spots on the upper half of corolla tube; inside cream with rounded maroon spots or dashes changing to concentric broken lines in lower half of tube; papillae up to 1.5 mm long and 0.75 mm broad at base; tube 10 mm long, 12 mm broad at mouth, pentagonal; lobes 8 mm long, 7.5 mm broad at base, spreading with recurved apex, deltoid, acute concave at tip, intermediate lobes 1.5 mm long. Outer corona lobes 5 mm diam. fused into disc or a slightly disc-like with short subquadrate crenate; inner lobes 3 mm long, 1 mm at base.

Distribution in Saudi Arabia.

Rare, known only from Najran Region, SW Saudi Arabia ( Plowes 2012).

General distribution.

Probably endemic to SW Arabian Peninsula, known so far only from Saudi Arabia

Habitat and ecology.

Concentrated amongst rounded granitic boulders at 500-1700 m alt. ( Collenette 1999). Flowering: March-April.

Diagnosis.

The variety is most similar to the Ethiopian endemic Huernia boleana , from which it can be separated with flowers by the much more campanulate corolla that is wider than the long, pentagonal tube, the more conical papillae and the shorter inner coronal lobes (ca. 3 mm compared to ca. 6 mm in H. boleana ) and with habit and habitat that is erect to decumbent amongst granitic rocks compared to H. boleana that is erect, pendulous or prostrate in basalt or sandstone.

It can be easily distinguished from the other varieties of C. lodarensis proposed here by the stout branches, flowers with more evenly-rounded spots inside that are more red in colour and by the more slender papillae.

Preliminary conservation status.

Ceropegia lodarensis var. rubrosticta has an estimated EOO of 97.188 km 2 (which would place the species in CR) and AOO of 20 km 2 (which would place it in EN). The size of populations and current threats are little known. Therefore, C. lodarensis var. rubrosticta should be considered Data Deficient ( DD).

Additional specimens examined.

Saudi Arabia - Najran • I. S. Collenette 6059 ( K [fl in spirit: 51184.000]); Al Jawshan , 70 km NW Najran; 18°8.4287'N, 43°51.2486'E; alt. 1520 m.; 07 Mar 1987 .

Figures

Map 6. Distribution of Ceropegia lodarensis var. rubrosticta.

Figure 14. Ceropegia lodarensis var. rubrosticta (H. rubrosticta) A ex S Collenette s. n. sub DP 7639, Al Jawshan, 70 km NW Najran (Type) B Collenette 1482, Jabal Manfah, 24 km NE Najran. Reproduced from Plowes (2012).

Figure 15. Ceropegia lodarensis var. rubrosticta A branch B side view of dissected flower C face view of gynostegium D side view of gynostegium E papillae inside corolla in mouth of tube F pollinarium. Drawn from (A, B 2, C) DP 7639, Al Jawshan, 70 km NW Najran; (B 1, D, E) Collenette 6059.