Heliophila roggeveldensis Al-Shehbaz, 2020

Al-Shehbaz, Ihsan A., 2020, Ten new species in the southern African genus Heliophila (Brassicaceae; Cruciferae), Phytotaxa 434 (1), pp. 65-88 : 81-83

Heliophila roggeveldensis Al-Shehbaz , sp. nov.

Diagnosis:— Heliophila roggeveldensis differs from the other annuals species of Heliophila with linear to filiform leaves lacking the nodal glands by having unappendaged oblanceolate petals 1.5–2 mm long, thick fruiting pedicels 3.5–4 mm long, ovaries with 5–7 ovules, submoniliform and often pendent fruit with thickened valve margins and flattened replum 0.4–0.5 mm wide.

Type:— SOUTH AFRICA. Northern Cape, [Namakwa, Karoo Hoogland], Farm Elandsfontein 47, Sutherland District, Roggeveld , 32º13ʹ2ʺS, 20º34ʹ37ʺE, 1502 m, 8 Oct. 2008, V. R. Clark & G. Coombs 805 (holotype, MO-6334880; isotype, GRA). Figure 9 .

Description: —Plants annual herbs, not glaucous. Trichomes straight, 0.04–0.05 mm long, restricted to lowermost part of stem below the cotyledons scars. Stems herbaceous, 4–8 cm tall, smooth, terete, erect to ascending, simple or few branched at base, glabrous except puberulent lowermost part. Basal leaves soon withered; cauline leaves not fleshy, sessile, blade simple, linear to filiform, 0.6–2.5 cm × 0.5–1.5 mm, entire at margin, not auriculate at base, without a pair of stipule-like glands at nodes, glabrous, base not decurrent or articulate. Racemes terminal, corymbose, 5–16- flowered, slightly elongated in fruit, secund or not in fruit; rachis straight, glabrous; fruiting pedicels without a pair of basal bract-like glands, not articulate at base, glabrous, rather stout, divaricate or horizontal to more often geniculately deflexed at base, straight or curved at base, persistent, lowermost 3–4 mm long; buds ovoid. Sepals ascending, oblong, 1.2–1.5 mm long, greenish pink, purplish when dry, glabrous, caducous, not cucullate at apex, not saccate at base. Petals white or pinkish, oblanceolate, 1.5–2 × 0.5–0.7 mm, ascending, obtuse at apex, unappendaged, not papillate; claw absent. Stamens slightly tetradynamous; filaments 1–1.2 mm long, glabrous at base, unappendaged; anthers ovate, 0.2–0.3 mm long, not apiculate at apex. Nectar glands lateral, median glands absent. Ovary glabrous; ovules 5–7 per ovary. Fruit dehiscent silique, capsular, linear, 0.9–1.4 cm × 1.4–1.7 mm, latiseptate, glabrous, slightly moniliform, constricted along replum, slightly torulose, divaricate to strongly reflexed; valves papery, midvein faint, lateral veins absent, margin thickened; replum flattened, 0.4–0.5 mm wide; gynophore 0.2–0.5 mm long; style in fruit 0.8–2.2 mm long, cylindrical, stout, glabrous; stigma entire. Seeds uniseriate, ovate, flattened, wingless, not margined, 1.3–1.7 × 1.1–1.2 mm; sinus wide.

Phenology: —Flowering September through October.

Distribution: —Roggeveld Mountains in Namakwa District of the Northern Cape and Central Karoo District of the Western Cape.

Etymology: —The species epithet is named after the Roggeveld Mountains to which it is apparently restricted.

Additional specimens examined (Paratypes): — SOUTH AFRICA. Northern Cape: [Namakwa, Karoo Hoogland], Farm Elandsfontein 47, Sutherland District, Roggeveld , 32º13ʹ2ʺS, 20º34ʹ37ʺE, 1502 m, 8 Oct. 2008, V. R. Clark & G. Coombs 774 ( GRA, MO) ; Roggeveld, Voelfontein , gate near watercourse below farmstead, 32º15ʹ47ʺS, 20º20ʹ44ʺE, 1273 m, 28 Sep. 2013, Heliophila Team-2013 NGS-153 A ( MO, NBG) . Western Cape: [Central Karoo, Laingsburg], Klein Roggeveld, road Matjiesfontein to Sutherland , 1–2 km of Nuwerus Farm , 32º56ʹ44ʺS, 20º33ʹ10ʺE, 1246 m, 27 Sep. 2013, Heliophila Team-2013 NGS-77 ( MO, NBG) .

Habitat: —Deep sandy-clay soil in Karoo shrubland, heavy clay soil in shrubland on dolerite; 1246–1502 m.

Discussion: — Heliophila roggeveldensis is most closely related H. clarkii which it differs from and resembles by several characters discussed under the latter. It resembles H. pusilla Linnaeus f. (1782: 297) in habit and in having linear to filiform, undivided leaves lacking the paired glands at the node, white petals, unappendaged filament bases, variously moniliform fruit, and wingless seeds. Indeed, it keys out in Marais (1970) to H. pusilla despite the fact that the differences between them are substantial. From the latter, H. roggeveldensis is easily distinguished by having sparsely puberulent (vs. glabrous) stems below the cotyledons scars, shorter stems to 8 (vs. 10–51) cm tall, stout (vs. slender) fruiting pedicels 3.5–4 (vs. 3.5–11) mm long, oblanceolate (vs. obovate) petals 1.5–2 × 0.5–0.7 mm (vs. 2–6 × 1.2–3 mm), glabrous (vs. sometimes papillate) filament bases, ovate (vs. oblong) anthers 0.2–0.3 (vs. 0.5–0.8) mm long, ovaries with 5–7 (vs. 6–14) ovules per locule, submoniliform (vs. strongly moniliform) fruit without (vs. usually with well-developed) narrow waists, thickened (vs. not thickened) valve margins, and flattened replum 0.4–0.5 (vs. 0.1– 0.2 mm wide). Furthermore, the two species are allopatric throughout their ranges, and H. pusilla is restricted to more westerly and southerly localities in the Western Cape alone and has not yet been reported from the Northern Cape.

Figures

FIGURE 9. Heliophila roggeveldensis. A. Fruiting plant. B. Portion of lowermost stem. C. Petal. D. Fruit and fruiting pedicel. E. Portion of fruit lateral side showing replum and portion of bulging valve covering seed.