Heliophila astyla 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 : 66-68

Heliophila astyla Al-Shehbaz , sp. nov.

Diagnosis:— Heliophila astyla is easily distinguished from the annual congeners with paired glands at the leaves and pedicels bases by having obsolete or no styles, strongly flattened and non-moniliform fruits, broadly winged seeds with a broad sinus, and filiform undivided or trisect leaves.

Type:— SOUTH AFRICA. [Western Cape, West Coast, Cederberg]. Clanwilliam , 300 ft [ca. 91 m], 4 July 1896, [ F. R. R.] Schlechter 8018 (holotype, G-00160865; isotypes, E-00199749, P-00739554 [excluding plants on top left and bottom right], Z-000089927). Figure 1 .

Description: —Plants annual herbs, not glaucous. Trichomes slender, straight, 0.09–0.18 mm long. Stems herbaceous, 15–26 cm tall, smooth, terete, erect, simple at base, glabrous except pilose lowermost part. Basal leaves soon withered; cauline leaves not fleshy, sessile, simple and trisect, blade or segments filiform, 2.5–6.5 cm × 0.3–0.5 mm, entire, not auriculate at base, with a pair of stipule-like filiform glands at node, glabrous, base not decurrent or articulate. Racemes terminal, lax, 8–16-flowered, elongated in fruit, not secund; rachis straight, glabrous; fruiting pedicels with a pair of basal bract-like filiform glands, not articulate at base, short pilose adaxially, slender, divaricate, straight, persistent lowermost 0.8–1.2 cm long; buds oblong. Sepals ascending, oblong, 1.7–2 mm long, glabrous, caducous, not cucullate at apex, not saccate at base. Petals white, oblanceolate, 2.3–2.5 × 1–1.2 mm, ascending, obtuse at apex, unappendaged, not papillate; claw absent. Stamens subequal; filaments 1.5–1.7 mm long, glabrous, unappendaged above base; anthers ovate, 0.5–0.6 mm long, not apiculate at apex. Nectar glands lateral, median glands absent. Ovary glabrous; ovules 10–16 per ovary. Fruit dehiscent silique, capsular, linear to linear-oblong, 1.4–1.9 cm × 2.4–2.7 mm, latiseptate, glabrous, not moniliform, straight along replum, torulose, divaricate; valves papery, midvein and lateral veins obscure, margin not thickened; gynophore 0.1–0.2 mm long; style obsolete or to 0.1 mm long, stout, glabrous; stigma entire. Seeds uniseriate, orbicular, flattened, winged, 1.6–2 mm in diam.; wing 0.2–0.4 mm wide, sinus wide.

Phenology: —July into August.

Distribution: —Known only from the type locality in Cederberg municipality of the Western Cape.

Etymology: —The species name is derived from the almost absence of the fruiting style.

Habitat: —Not recorded.

Discussion: —The type collection of Heliophila astyla was misidentified by its collector as H. chamaemelifolia Burch. ex Candolle (1821b: 689) which is currently considered a synonym of H. crithmifolia Willdenow (1809: 682) . The last species is substantially different from the novelty by having pinnatisect, 5–9-lobed (vs. entire or trisect) leaves, obovate (vs. oblanceolate) and usually purple to mauve or pink (vs. white) larger petals (4–)5–8(–10) × 1.8– 3.5(–5) mm (vs. 2.3–2.5 × 1–1.2 mm), ovaries with (18–)20–42 (vs. 10–16) ovules, fruiting pedicels (1–)1.4–4.7 (vs. 0.8–1.2) cm long, larger fruit 2.5–5.5(–6) cm × 2.5–4.3(–5) mm (vs. 1.4–1.9 cm × 2.4–2.7 mm), longer styles 0.5–3 (vs. obsolete or to 0.2) mm long, and seeds with rather narrow (vs. wide) sinus. In fact, the type collection of H. astyla represents plants of the new species alone (E, G, Z duplicates), plants of H. variabilis Burch. ex Candolle (1821b: 683) alone (K duplicate), or plants of both species (P duplicate). The latter species is unique in the genus by having papillate, subspherical to clavate trichomes, and it also differs from H. astyla by having pinnatisect leaves, larger petals ((4–)5–8(–10.5) × (2–) 3–6.5 mm) and fruits (1.7–)2–4(–4.5) cm × 2–2.5(–2.8) mm, and distinct styles 0.5–2 mm long. Heliophila astyla does not seem to be closely related to any of the congener annuals that have paired glands at the leaf and pedicel bases, non-pinnatisect leaves, strongly latiseptate non-moniliform fruit, obscurely 1-veined valves, and strongly flattened, broadly winged seeds each with a broad sinus.

Perhaps the nearest relative of Heliophila astyla is H. obibensis Marais (1966: 104) , which it resembles in the overall morphology. However, the latter is restricted to Namibia and adjacent Richtersveld municipality of the Northern Cape (vs. Cederberg municipality of the Western Cape) and differs by having moniliform (vs. nonmoniliform) fruits with constricted (vs. straight) replum, wingless (vs. broadly winged) seeds, distinct styles 0.4–1 mm long (vs. obsolete or to 0.1 mm long), fewer (8–10 vs. 10–16) ovules per ovary, and exclusively simple (vs. simple and trisect) leaves.

Figures

FIGURE 1. Heliophila astyla. A. Plant. B. Petal. C. Fruit and fruiting pedicels. D. Seed. Drawn by Al-Shehbaz from holotype (G- 00160865).