Heliophila xylopoda 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 : 85-87

Heliophila xylopoda Al-Shehbaz , sp. nov.

Diagnosis:— Heliophila xylopoda is readily separated from related shrubby, scabrous papillate taxa with densely imbricate leaves and intercalary infructescences by having latiseptate, ovate silicles with a prominent midvein and 3 or 4 ovules per ovary.

Type:— SOUTH AFRICA. Western Cape, Central Karoo District, Laingsburg, top and upper slopes of Witteberg, 7 Aug. 1976, Peter Goldblatt 3788 (holotype, MO-2420820). Figure 11 .

Description: —Plants subshrubs, not glaucous, scabrous. Trichomes papillate, straight, 0.03–0.15 mm long. Stems woody throughout except current-year growth, ca. 20 cm tall, smooth scabrous papillate but not in rows, not striate ridged or winged, terete, stout, erect or ascending, branched, with prominent scars of leaf bases. Leaves cauline, densely imbricate, appressed to stem, fleshy; petiole absent; blade simple, oblong to narrowly so, 3–8 × 1–2 mm, entire, undivided, sessile, not auriculate at base, with a pair of early caducous stipule-like, short subulate glands at node, scabrous papillate, base articulate, not decurrent. Racemes terminal in flower but becoming intercalary by the continuous growth of shoot apex, corymbose, 4–12-flowered, not elongated in fruit, not secund; rachis straight scabrous papillate; fruiting pedicels with a pair of basal, early caducous bract-like glands, not articulate at base, scabrous papillate all around, slightly stout, ascending, straight, persistent, 3–6 mm long; buds ovoid. Sepals ascending, oblong, 3–4 mm long, with a white margin to 0.5 mm wide, glabrous or sparsely papillate, caducous, median pair slightly cucullate at apex, lateral pair slightly saccate at base. Petals white, drying maroon on outside, obovate, 5–7 × 3–4 mm, ascending, obtuse at apex, unappendaged, not papillate at base; claw absent. Stamens slightly tetradynamous; filaments 2.5–3.5 mm long, glabrous, unappendaged above base; anthers oblong, ca. 1 mm long, not apiculate at apex. Nectar glands lateral, U-shaped, median glands absent. Ovary glabrous; ovules 3 or 4 per ovary. Fruit dehiscent silicle, capsular, ovate to ovate-elliptic, 4–6 × 2.5–3.5 mm excluding style, latiseptate, glabrous, not moniliform, straight along replum, not torulose, ascending; valves subleathery, 1-veined, midvein prominent, lateral veins distinct, margin not thickened; gynophore obsolete; style in fruit 2.5–3 mm long, cylindrical, slender, glabrous; stigma entire. Seeds aseriate, ovate, flattened, wingless, margined, ca. 3 × 1.5 mm; margin 0.15–0.25 mm wide; sinus wide, open.

Phenology: —Flowering August perhaps through September.

Distribution: —Endemic and known thus far only from the two collection from the top of Witteberge Range in Laingsburg municipality of the Central Karoo District, Western Cape.

Etymology: —The species epithet means a woody foot that characterizes the lower stems.

Additional specimen examined (Paratype): — SOUTH AFRICA. Western Cape, Central Karoo District, Laingsburg, Top of Witteberg, Matjiesfontein, near radiomast, 29 Sep. 1983, 4800ʹ [1463 m], L. van Zyl 3564 (NBG 0218379-0).

Habitat: —Rocky sandstone soil and quartzite in dry fynbos vegetation.

Discussion: — Heliophila xylopoda is most closely related to H. cedarbergensis Marais(1966:101) and H. dregeana Sonder (1846: 260) , all of which are subshrubs with initially terminal racemes in flower that become intercalary in fruit due to the vegetative growth at shoot apex, as well as by having deciduous, paired glands at attachment base of leaves and pedicels and fleshy, papillate, overlapping leaves not decurrent at base. From H. cedarbergensis , H. xylopoda is easily distinguished by having densely long papillate and oblong (vs. glabrous or obscurely papillate and oblanceolate to lanceolate-elliptic) leaves, ovate to ovate elliptic silicles (vs. lanceolate siliques) only 0.3–0.6 (vs. 1.5–4) cm long, petals 5–7 (vs. 10–12) mm long, and 3 or 4 (vs. 8–12) ovules per ovary. The novelty is distinguished from H. dregeana by having ovate to ovate-elliptic and latiseptate silicles 4–6 × 2.5–3.5 mm, valves with a prominent midvein, stems with coarse papillae not arranged in stripes, petals 5–7 mm long, and flattened, ovate, narrowly margined seeds. By contrast, H. dregeana has linear, terete, moniliform fruit, (1–) 1.3–1.8 cm × 1.2–1.7 mm, obscurely veined valves, stems with minute cartilaginous papillae often arranged in longitudinal stripes, petals 7–11(–14) mm long, and plump, globose, non-margined seeds.

Figures

FIGURE 11. Heliophila xylopoda A. Plant. B. Leaf. C. Sepal. D. Petal. E. Fruit and fruiting pedicel. Drawn by Al-Shehbaz from holotype (MO-2420820).