Phymaspermum trifidum 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 : 440-441

4. Phymaspermum trifidum Magee and Ruiters sp. nov.

— TYPE: SOUTH AFRICA. Western Cape, Worcester (3319): Farm Goedemoed , between Robertson and McGregor (–DD), 28 November 2012, Magee and Boatwright 512 (holotype: NBG!; isotypes: BOL!, K!, PRE!, S!)

Single-stemmed, densely leafy shrub, 0.7 m high. Stem much-branched; branches erect to spreading, silvery pubescent; fascicles sometimes present in leaf axils. Leaves alternate, spreading, 5.0–17.0 × 0.8–1.0 mm, linear, mucronate, rarely entire (entire on peduncles), trifid, narrowed into petiole-like base, without secondary basal lobes, silvery sericeous on both surfaces, fleshy; basal swelling present, continuous with stem ribs; lobes 3, 1.0–8.0 × 0.8–1.0 mm, linear, mucronate. Capitula radiate, heterogamous, terminal, solitary, pedunculate; peduncles 20.0–40.0 mm long, silvery pubescent. Involucre 5.0–6.0 × 6.0–7.0 mm, hemispherical to cyathiform, not tapering at the base; involucral bracts 3- or 4-seriate, tightly arranged, margins and apices scarious, membranous apices of all bracts 0.3–1.3 mm long, pubescent, brown margins present, median resin canals present; outer bracts lanceolate to ovate, 2.1–2.4 mm long, acute to rounded; middle bracts lanceolate to ovate, 2.2–2.6 mm long, rounded; inner bracts ovate, 3.0–4.0 mm long, rounded; innermost bracts linear to oblong, 4.5–4.8 mm long, rounded. Receptacle convex; paleae in marginal series, linear to oblong, 4.3–5.9 mm long, rounded, rigid with scarious margins and apices, scarious apices 1.0–2.0 mm long. Ray florets 12 to16; tube 1.4–1.7 mm long; limb obovate, 7.2–7.7 × 3.1–3.5 mm, apically 3-dentate, white. Disc florets 30–40, without resin canals; corolla 1.7–2.0 mm long, with only glandular trichomes, yellow; tube 1.0– 1.1 mm long; limb campanulate, 0.7–1.0 mm long (excluding lobes); lobes spreading, ± 0.6 mm long, triangular. Anthers 2.0– 2.7 mm long (including apical appendage); apical appendage obovate. Style 2.0– 2.1 mm long (excluding branches); branches 0.4–0.6 mm long. Cypselas 1.7 × 0.7 mm, oblong to obovate, 11-ribbed, apical rim absent, glandular trichomes present, dense, scattered, mucilaginous when soaked, discontinuous resin canals in ribs absent. Figure 7 .

Diagnostic Characters — Phymaspermum trifidum is closely related to P. thymelaeoides with which it shares the radiate heads, slightly fleshy, silvery sericeous leaves and hairy involucral bracts. Phymaspermum trifidum can however be distinguished by the consistently trifid leaves, the broad membranous appendages on the innermost involucral bracts and the glabrous disc floret tubes.

Distribution and Ecology — Phymaspermum trifidum appears to be highly restricted and is known from only three localities between McGregor and Bonnievale. It grows in alluvial sand at an altitude of around 150–200 m ( Fig. 7G ). Flowering appears to be from August to November. This species is reported to be well grazed ( Van Breda 4130, PRE).

Additional Specimens Examined — SOUTH AFRICA. Western Cape: 3319 (Worcester): Farm Goedemoed , between Robertson and McGregor (–DD), Helme 7480 (NBG). 3320 (Montagu): Bonnievale , Kapteinsdrift (–CC), Van Breda 4130 (PRE); Robertson, along road to Stormsvlei (–CC), Van Breda 805 (PRE two sheets) .

Figures

FIG. 7. Phymaspermum trfidum. 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: A1, B–E. Van Breda 4130 (PRE); A2, F. Magee and Boatwright 512 (NBG). Scale: A–B = 4 mm; C–D = 1 mm; E = 500 μm.