Ceropegia khalidbinsultanii (Plowes & McCoy) 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

2. Ceropegia khalidbinsultanii (Plowes & McCoy) Alharbi & Al-Qthanin comb. nov. Figs 6 , 7 ; Map 2

Huernia khalidbinsultanii ≡ Huernia khalidbinsultanii Plowes & McCoy, Cact. Succ. J. (Los Angeles) 75(1): 19 (2003). Type: Saudi Arabia - Asir • T. A. McCoy 2446 (holotype: MO; isotypes P & SRGH); 25 km SW of Khamis Mushayt ; 18°4.0906'N, 42°43.8908'E; alt. 2100 m; 15 Jan 1999 .

Huernia asirensis = Huernia asirensis Plowes , Asklepios 114: 7 (2012), syn. nov. Type : Saudi Arabia - Tanumah • I. S. Collenette 2655 (Holotype: K!, [fl in spirit: 44279.000]); 12 km S. of An Numas on Taif to Abha Road; 18°56.1481'N, 42°11.2139'E; alt. 1800 m; 10 May 1981 .

Huernia radhwana = Huernia radhwana Plowes , Asklepios 114: 10 (2012), syn. nov. Type : Saudi Arabia - Jabal Radhwa • I. S. Collenette 5944 (Holotype: K!, [fl in spirit: 51187.000]); 75 km NE Yanbu; 24°32.3717'N, 38°20.4741'E; alt. 1750 m; 01 Feb 1987 .

Huernia anagaynensis = Huernia anagaynensis Plowes, Asklepios 114: 7 (2012), syn. nov. Type : Saudi Arabia - Jabal Anagayn • I. S. Collenette 5970 (Holotype: K!, [fl in spirit: 50937.000]); 95 km south of Madinah; 23°21.5747'N, 39°34.9766'E; alt. 1371 m; 06 Dec1986 .

Huernia haddaica Al-Hemaid (nom. inval. Art 37.2), Saudi J. Biol. Sci. 8: 168 (2001).

Description.

Dwarf succulent forming dense clump. Branches 50-100 mm long, non-rhizomatous, decumbent, grey-green mottled with purple-red; tubercles 7-16 mm long (including leaf-rudiment), 1.5-5 mm broad at base, conical, spreading, laterally flattened and joined into 5 angles along stem, each tipped with a soft slender acuminate caducous leaf- rudiment. Inflorescence usually only 1 per branch, arising in lower half of branch, each bearing 1-7 flowers developing mainly simultaneously or in gradual succession from short peduncle, with several filiform bracts without lateral teeth, flowers with mainly very foetid odour, rarely faint or no unpleasant smell; pedicel 5-21.5 mm long, 1-2 mm thick, spreading and holding flower facing horizontally, tapering sometimes toward the point of flower attachment; sepals 10-18 mm long, 1-2 mm broad at base, attenuate. Corolla 27-47 mm diam., tubular-campanulate to campanulate; outside smooth, white to creamy-white or cream speckled with pale maroon spots uniformly scattered, sometimes spots become darker especially on the lower or upper half of corolla tube, with 1 heavy (+ 2 lighter) raised longitudinal veins running from lobes to base of tube; inside creamy-white to cream with irregular-shaped narrow short maroon lines and dashes changing to narrow concentric broken lines in lower half of tube, covered except in lower third of tube with slender (hair-like) papillae densely crowded around mouth of tube (up to 3 mm long and 0.75 mm an base in tube mouth), each tipped by minute apical acuminata bristle; tube 7-13 mm long, 9-14 mm broad at mouth, pentagonal; lobes 13-18 mm long, 8-12 mm broad at base, ascending to slightly spreading, narrowly deltoid and usually longer than wide, attenuate usually concave or form channel above, intermediate lobes 1-2.5 mm long. Corona without basal stipe; outer lobes (4.5-8 mm diam.) spreading on base of tube and fused partially to it; fused together into disc with crenate margin to a slightly disc-like with rounded to subquadrate short and broad lobes, rarely discrete to 5-lobed with each lobe subquadrate mucronate, blackish maroon; inner lobes 3-5.5 mm long, 0.5-1.5 mm at base, ivory white sometimes mottled with a few maroon spots at the tips, adpressed to anthers in their lower half then rising up connivent and then diverging towards apices, dorsiventrally flattened around laterally-broadened base becoming terete above and tapering gradually to a slender fine minutely-scabrous apex, at base with inflated transversal dorsal gibbosity with rounded to acute end. Pollinia 0.1-0.7 mm long.

Distribution in Saudi Arabia.

Scattered over a wide area, extending from Khamis Mushait in SW of the country to Jabal Radhwa, 75 km north of Yanbu in the Western Region.

General distribution.

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

Habitat and ecology.

Growing on granitic outcrops often under shrubs, from 1800-2100 m alt. Flowering Dec.-May

Diagnosis.

Ceropegia khalidbinsultanii is best distinguished from the closely-related C. lodarensis by longer tubercles (up to 16 mm) on the branches and the smaller, white to creamy-white tubular-campanulate corolla streaked with narrow maroon lines, slender (hairy) papillae and a very foetid odour.

Notes.

The foetid odour of the flower becomes weak or completely vanishes after all pollinia have been removed from the flower.

Etymology.

Khalidbinsultanii for Prince Khalid bin Sultan bin Abdulaziz M., a former Saudi Deputy Minister of Defence ( Plowes and McCoy 2003).

Preliminary conservation status.

Near Threatened ( NT) has been assigned to Ceropegia khalidbinsultanii , based on the species’ EOO of 41,490 km 2 and AOO of 2,012 km 2 and the current threats of habitat transformation (roads and housing construction), population fragmentation and tourism.

Additional specimens examined.

Saudi Arabia - Al-Taif • S. A. Alharbi S3 a ( UQU); Wadi Thee Gazal , Ash Shafa; 21°5.5702'N, 40°21.785'E; alt. 2057 m; 23 Jan 2011 ; S. A. Alharbi S4 a ( UQU); same data as for preceding; 1 Jan 2011 ; S. A. Alharbi S6 a ( UQU); same data as for preceding; 10 Jan 2011 ; S. A. Alharbi S7 a ( UQU); same data as for preceding; 9 Dec 2010 ; S. A. Alharbi S8 a ( UQU); same data as for preceding; 19 Jan 2011 ; S. A. Alharbi S16 a ( UQU); same data as for preceding; 8 Jan 2011 ; S. A. Alharbi S16 A ( UQU); same data as for preceding; 30 Dec 2010 ; S. A. Alharbi S13 a ( UQU); same data as for preceding; 9 Dec 2010 ; S. A. Alharbi S14 a ( UQU); same data as for preceding; 17 Dec 2010 ; S. A. Alharbi S 00 ( UQU); 9 Dec 2010 ; S. A. Alharbi S10 b ( UQU); same data as for preceding; 21°5.4656'N, 40°21.7937'E; 9 Dec 2010 .

Figures

Map 2. Distribution of Ceropegia khalidbinsultanii.

Figure 6. Ceropegia khalidbinsultanii A Alharbi S 00 (H. asirensis) B Alharbi S 10 b (H. asirensis) C Alharbi S 4 a (H. asirensis) D Collenette 5944, Jabal Radhwa, (H. radhwana, Type) E Alharbi S 16 a (H. asirensis) F Collenette 1309, Al-Baha, (H. asirensis, Type) G Collenette 5970, Jabal Anagyan (H. anagaynensis, Type) H ex Tom McCoy KSA 129 sub DP 8384, 25 km SW of Khamis Mushayt, (H. khalidbinsultanii, Type) I follicles, Alharbi S 14 a. (A-C, E, I) photo by the first author from Wadi Thee Gazal, Ash Shafa; (D, F, G) reproduced from Plowes (2012)); (H) received from D. Plowes in 2011.

Figure 7. Ceropegia khalidbinsultanii 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 S. A. Alharbi S 4 a, Wadi Thee Gazal, Ash Shafa.