Phymaspermum aphyllum Magee and Ruiters, 2016

Ruiters, Ashton K., Tilney, Patricia M., Wyk, Ben-Erik Van & Magee, Anthony R., 2016, Taxonomy of the Genus Phymaspermum (Asteraceae, Anthemideae), Systematic Botany (Basel, Switzerland) 41 (2), pp. 430-456 : 442

6. Phymaspermum aphyllum Magee and Ruiters sp. nov.

— TYPE: SOUTH AFRICA. Western Cape, Montagu (3320): Along road between Ladismith and Laingsburg, in road reserve (–BD), 2 June 2007, Vlok & Schutte 596 (holotype: NBG!; isotype: K!)

Single-stemmed, very sparsely leafy shrub, 0.5–1.0 m high. Stem much-branched; branches erect to spreading, spinetipped, densely white wooly between ribs; fascicles rarely present in leaf axils. Leaves alternate, very sparse, caducous, apressed to erect, 2.0–20.0 × 0.5 mm, linear, mucronate, revolute, entire, without petiole-like base, without secondary basal lobes, glabrous on both surfaces, fleshy to leathery; basal swelling present, continuous with stem ribs. Capitula radiate, heterogamous, terminal, solitary, with 0–1 additional capitula from leaf axils below, pedunculate; peduncles 25.0–38.0 mm long, silvery pubescent. Involucre 5.0–6.0 × 6.0–9.0 mm, hemispherical, rarely tapering at the base; involucral bracts 4-seriate, tightly arranged, margins and apices scarious, membranous apices of all bracts 0.3–0.5 mm long, silvery villous, brown margins absent, median resin canals present; outer bracts lanceolate, 1.5–1.6 mm long, acute; middle bracts lanceolate, 2.0– 2.2 mm long, acute; inner bracts lanceolate to oblong, 2.5–3.5 mm long, acute to obtuse; innermost bracts oblong, 3.5 mm long, rounded. Receptacle convex; paleae in marginal series, narrowly oblong, 3.0– 4.5 mm long, rounded, scarious. Ray florets 9–10; tube 2.0– 2.8 mm long; limb obovate, 5.7–11.4 × 3.2–4.0 mm, apically 3-dentate, white. Disc florets ± 50, without resin canals; corolla 1.6–2.0 mm long, with only glandular trichomes, yellow; tube 0.7–1.0 mm long; limb campanulate, 0.7–1.8 mm long (excluding lobes); lobes spreading, 0.5–0.7 mm long, triangular. Anthers 2.0– 2.4 mm long (including apical appendage); apical appendage oblong. Style 2.0– 2.2 mm long (excluding branches); branches 0.4 mm long. Cypselas 2.0–2.5 × 0.5–0.8 mm, obovate, 10- to 11-ribbed, apical rim absent, glandular trichomes present, dense, scattered, mucilaginous when soaked, discontinuous resin canals in ribs absent. Figure 9 .

Diagnostic Characters — Phymaspermum aphyllum has in the past been incorrectly identified as P. junceum (Berg.) Less. (the latter now a synonym of Osteospermum junceum, Magee et al. 2013 ). It is a sparsely leafy shrub with caducous leaves, ± 0.5 mm wide, longitudinally white striped stems which are densely white wooly between the ribs and persistent peduncles which often become spinescent. It differs further from the closely related P. leptophyllum by the obviously ribbed cypselas with prominently stalked myxogenic trichomes. In P. leptophyllum the cypselas appear unribbed and the myxogenic trichomes appear sessile due to the prominently elongated epidermal cells.

Distribution and Ecology — Phymaspermum aphyllum is known from only a handful of localities between Barrydale and the Witteberg in the Little Karoo at an altitude of around 700 m ( Fig. 9G ). The leaves of this species are apparently highly palatable for livestock (Vlok and Schutte-Vlok pers. comm.). Flowering is from June to December.

Additional Specimens Examined — SOUTH AFRICA. Western Cape: 3320 (Montagu): 14 miles SSE of Laingsburg (–BB), Acocks 20509 (PRE); Ladismith, Farm Comae , near Plathuis Station (–DB), Van Breda 4407 (PRE); Swellendam, “Poortfontein”, along Barrydale/ Ladismith road (–DD), Van Breda 4545 (PRE) .

Figures

FIG. 9. Phymaspermum aphyllum. A. Leaves. B. Capitula. C. Involucral bracts (outermost to innermost series, from left) and single palea (far right). D. Disc floret. E. Ray floret. F. Cypsela. G. Known geographical distribution. Vouchers: A, C–E. Van Breda 4407 (PRE); B, F. Van Breda 4545 (PRE). Scale: A–B = 4 mm; C–D = 1 mm; E = 500 μm.