Convolvulus hamrinensis Rech.f., Anz. Oesterr . Akad. Iss., Math.-Naturwiss. Kl. 98: 11. 1961. (Rechinger 1961: 11).

Wood, John R. I., Williams, Bethany R. M., Mitchell, Thomas C., Carine, Mark A., Harris, David J. & Scotland, Robert W., 2015, A foundation monograph of Convolvulus L. (Convolvulaceae), PhytoKeys 51, pp. 1-282 : 182

173. Convolvulus hamrinensis Rech.f., Anz. Oesterr. Akad. Iss., Math.-Naturwiss. Kl. 98: 11. 1961. (Rechinger 1961: 11). Figure 25, t. 36-42

Convolvulus oxyphyllus subsp. sheilae R.R.Mill, Edinburgh J. Bot. 70: 376. 2013. ( Mill 2013: 376. Type. SAUDI ARABIA, Collenette 2836 (holotype E!; isotype K!).

Convolvulus infantispinosus R.R.Mill, Edinburgh J. Bot. 70: 374. 2013. ( Mill 2013: 374). Type. SAUDI ARABIA, Collenette 2210 (holotype E!; isotype K!).

Type.

IRAQ, Rechinger 8083 (holotype W!; isotype E00699568!).

Description.

Undershrub with spinescent branches forming a low bush to 60 cm high and up to 1 m wide; young branchlets white-tomentellous, side branches rather short, c. 5 cm long, sometimes spine-like. Basal leaves 0.5-3 × 0.3-0.6, oblanceolate, obtuse, margin undulate, base attenuate into a long petiole-like base, densely puberulent on both surfaces, paler beneath; stem leaves and bracts 3 × 2 mm, oblong to oblanceolate, obtuse to subacute, cuneate at base. Flowers 1 (-2), sessile in the axils of bracts; bracteoles 2 × 0.5 mm, linear-oblong, pedicels 0-1 mm; sepals 5-6 × 2-3 mm, oblong to oblanceolate, obtuse, densely pilose; corolla 0.6-1cm long, white, slightly lobed, midpetaline bands pilose; ovary hirsute, style glabrous, divided c. 4 mm above base, stigmas 4 mm. Capsule not seen.

Distribution.

Locally abundant principally in sandy desert: Syria (?); Iraq (Guest et al. 16151B, Mohallal 19504, both sterile); Saudi Arabia: Jouf, Hail, Riyadh to Eastern Province. Mandaville 199, 217, 2271, 2328, 2465, 2485, 3124, 3208; Popov 69/224, 72/57: Chaudhary 3467; Wood 71/269; Philby s.n. [15/8/1931]; Vesey-Fitzgerald 15888; Hillcoat 364; Dickson 1074; Collenette 97, 1851, 5332, 7214, 7879, 7883, 7886. The type is from east of Baghdad but the numerous records from Saudi Arabia seem indistinguishable.

Notes.

Arabian specimens of this species have been misidentified as Convolvulus lanatus . The type of Convolvulus infantispinosus (Collenette 2210) has more delicate spines but seems to be only a form of Convolvulus hamrinensis .

This species possibly intergrades with Convolvulus oxyphyllus but is nearly always easily identified. The plant has a characteristic appearance with short rigid spine-like side branches to the stiff woody spinescent main stem. Leaves and bracts are typically obtuse, the lower leaves petiolate. Flowers are solitary (rarely paired) axillary, usually much exceeding the rather inconspicuous bracts. At one extreme a few specimens (Collenette 5351, Rechinger 9886, Chaudhary 3467, Omar et al. 43961) have acute leaves and bracts, clearly approaching Convolvulus oxyphyllus . At the other extreme, specimens with obtuse, undulate leaves and bracts are found (Collenette 1851, 5332, 7874, Mandaville 7850). Collenette 1851 is especially close to the type of Convolvulus hamrinensis .