Euphorbia pseudocontorta Bruyns, 2020

Bruyns, Peter V., 2020, A further new species of Euphorbia (Euphorbiaceae) from Moçambique, Phytotaxa 433 (4), pp. 297-300 : 299-300

Euphorbia pseudocontorta Bruyns , sp. nov.

This new species differs from E. contorta by the many 3- to 4-angled branches that arise from ground-level to form a low and relatively dense shrub and by the longer peduncles beneath the cymes and the lateral cyathia.

Type:–– MOÇAMBIQUE. Zambézia Prov.: 60 km north-east of Molócuè (1538 CA), ± 500 m, 22 December 1998, Bruyns 7795 (holotype BOL! , isotype NBG! ). ( Figs 1 , 2 )

Bisexual spiny glabrous succulent shrub 0.15–0.3 × 0.3–0.5 m with many branches from similar stem, densely branched at ground level, with fibrous roots arising from base. Branches ascending to ± prostrate, 100–200 × 15–25 mm, 3- to 4- angled, not constricted into segments, smooth, pale grey-green with paler stripes between angles; tubercles fused into 3 or 4 angles, laterally flattened and truncate, projecting ± 5 mm from branch, with spine-shields 5–7 mm long, 3–5 mm long and rounded below spines but remaining well separated from next, bearing 2 spreading initially purple-red (later grey) spines ± 10 mm long; leaf-rudiments on tips of new tubercles towards apex of branches, 8–10 × 5–6 mm, erect, fleeting, ovatelanceolate, sessile, with small prickles ± 1.5 mm long on either side at base. Inflorescences many per branch usually towards apex, each a solitary cyme in axil of tubercle, sessile, each cyme with 3 transversely disposed cyathia, central male, lateral 2 bisexual and developing later each on short peduncle 2–3 × ± 1 mm, with 2 ovate bracts ± 2 × 1–2 mm subtending lateral cyathia; cyathia shallowly funnel-shaped, glabrous, ± 5 mm broad (3 mm long below insertion of glands), with 5 pinkish red obovate lobes with deeply incised margins, grey-green variably suffused with red; glands 5, transversely rectangular and contiguous, 2.5–3 mm broad, dark yellow with red outer margins, spreading, inner margins slightly raised, outer margins entire and spreading; stamens glabrous, red, bracteoles enveloping groups of males, with finely divided red tips, glabrous; ovary 3-angled, glabrous, green, raised on pedicel ± 1 mm long; styles ± 2.5 mm long, pinkish, branched to near base. Capsule ± 4 mm diam., obtusely 3-angled, reddish green, glabrous, nearly sessile.

Distribution & habitat:–– Euphorbia pseudocontorta is only known in the central province of Zambézia, where it is found in shallow pockets of soil on low granitic domes at altitudes of 500– 600 m. Plants are common in shallow soils on otherwise fairly bare rocks.

Discussion:––This new species is similar to E. contorta , which occurs in shallow soil on granitic outcrops around the bases of larger hills some 150 km further to the north-west at elevations of 550– 700 m. Euphorbia contorta is sparingly branched, with the stem usually rising rather obliquely to 1 m or more and a few horizontal branches spreading from it along its length. The new species is densely branched from the base, with the stem not visible among the branches. In E. contorta the stem and branches are an unmarked dull grey and are (4–)5- to 7-angled while in the new species they have a paler longitudinal patch between the angles and are 3- to 4-angled. Florally the two differ in the longer peduncles in E. pseudocontorta , both in the peduncle beneath the cyme and in the peduncles beneath each of the lateral cyathia in the cyme.

Conservation status:––Not threatened.

Additional specimen examined: MOÇAMBIQUE. Zambézia Prov.: 11 km south of Alto Ligonha (1538CA), 570 m, 11 November 2000, Bruyns 8538 (BOL).

Figures

FIGURE 1. Known distribution of Euphorbia pseudocontorta.

FIGURE 2. Euphorbia pseudocontorta. A, young spine-complex and leaf-rudiment from above (scale 2 mm, as for B–E). B, young spine-complex and leaf-rudiment from side. C, side view of cyme in first male stage. D, side view of cyme in female stage. E, face view of cyathium. F, anther and bracteoles (scale 1 mm, as for G). G, female floret inside dissected cyathium. A, B, C, E drawn by P.V. Bruyns from Bruyns 8538, south of Ligonha, Moçambique. D, F, G from Bruyns 7795, NE of Molocue, Moçambique.