Polhillia pallens C.H.Stirt., 1986

du Preez, B., Dreyer, L. L., Stirton, C. H. & Muasya, A. M., 2021, A monograph of the genus Polhillia (Genisteae: Fabaceae), South African Journal of Botany 138, pp. 156-183 : 177-178

9. Polhillia pallens C.H.Stirt. ( Fig. 18 ), S Afr. J. Bot. 52: 2 (1986).

Type: South Africa, Western Cape, 3420 (Bredasdorp): 3 km west of Breede River mouth on south side of river along access road to Kontiki (— BD), 22 Feb 1981, C.J. Burgers 2633 ( NBG, holo.!; K, PRE iso!)

Erect shrubs 1.5 — 2.5 m tall, loosely branching, sprouting from a woody rootstock. Branches greyish-brown, glabrescent, lenticels prominent. Stipules 1.5 — 3.0 mm long, silvery. Lea fl ets ellipticaloblong, silvery, adpressed sericeous-canescent, flattened to partially conduplicate, apex acute-obtuse, base acute-attenuate, terminal leaflet 3.5 — 7.0 X 1.0 — 3.0 mm, lateral leaflets 3.0 — 6.5 X 1.0 — 3.0 mm; leaves subsessile. In fl orescence 1 — 2 flowered terminal cluster, subsessile; pedicel up to 2.0 mm long; bract 1.0 mm long, linear. Flowers yellow, 10.0 — 11.5 mm long. Calyx 4.0 — 4.5 mm long, yellow-green, sometimes flushed maroon, villous; tube 2.5 — 3.0 mm long; dorsal teeth broadly triangular, 1.5 — 2.0 mm long, fused for less than one third of their length, tips acute-obtuse; ventral teeth triangular, 1.5 — 2.0 mm long, fused to about two thirds the lobe length, spreading, apex acute. Standard 10.0 — 12.0 mm long, claw linear, 3.0 — 4.0 mm long, lamina broadly ovate, 8.0 — 8.5(— 10.0) X 10.0 — 13.0 mm, apex emarginate, base cordate, back sericeous except along margin. Wing petals 9.5 — 11.0 mm long, equal to or slightly longer than keel; claw 3.2 — 4.0 mm long; lamina obliquely-oblong, 7.5 — 8.0(— 9.0) X 4.0 — 4.5 mm, pilose along midline, apex rounded-truncate, base broadly auriculate, lunate depression with lamellate sculpturing. Keel petals 9.0 — 10.5 mm long, claw 3.5 — 4.5 mm long, lamina obliquely-oblong, 7.0 — 8.0 X 3.8 — 4.5 mm, pilose along fore half, apex rounded, base triangular-auriculate. Stamens basifixed anthers 1.2 — 1.3 mm long, carinal anther 1.1 mm long, dorsifixed anthers 0.8 mm long; staminal tube 6.7 — 8.5 mm long, unfused portion remaining closely united, tightly arranged around the style. Pistil 8.2 — 10.2 mm long; ovary 4.6 — 6.3 X 0.9 — 1.2 mm, ovules 9; style usually at 70 — 90̊ angle, height of curvature 2.7 — 3.6 mm, glabrous, except basally. Fruit indehiscent, non-plicate, straight, fibrous, sericeous, olive green, 18.0 — 30.0 X 3.0 — 3.5 mm. Seed ovate-reniform, testa olive-green to dark-brown, smooth, 2.0 — 2.9 X 1.8 — 2.2 mm, 1.6 — 1.9 mm thick.

Etymology

The specific epithet “pallens ” refers to the pale silvery leaves of this species.

Diagnostic characters

Polhillia pallens is morphologically variable, especially in terms of the shape of the wing and keel petals, but not to an extent that would warrant further recognition of separate taxa. It can be distinguished from P. curtisiae and P. xairuensis by its adpressed sericeous-canescent, grey leaflets (versus densely spreading villous, blue-green leaflets); unfused parts of stamens remaining closely united around the style, style erect at 70 — 90̊ angle (versus unfused parts of stamens loosely spread around style, style sub-erect at 45 — 60̊ angle); and by being a tall, sparsely branched shrub of up to 2.5 m tall (versus erect, rounded shrub with dense terminal burst branching, 0.5 — 1.0 m or 1.0 — 1.8 m tall, respectively).

Distribution, ecology and conservation status

Polhillia pallens flowers from April to August, with one odd record from February. It was previously broadly circumscribed to include both P. stirtoniana and P. xairuensis . It is restricted to only a few sites along and near the lower Breede River region ( Fig. 6B ), where it grows in clay soil in Eastern Ruens ^Shale Renosterveld (FRs 13) and in transitional vegetation with Overberg Dune Strandveld (FS 7) on the southern banks of the Breede River ( Mucina and Rutherford, 2006). This species is threatened by continued agricultural expansion, habitat fragmentation and by severe alien species encroachment at the type locality. Some populations are, however, still healthy and plants grow abundantly in at least three of the known sites. The Red Data List status of this species is proposed as Vulnerable (VU A2c; B 1ab(iii,iv,v)+ B 2ab(iii,iv,v)) following the latest IUCN categories and criteria ( IUCN, 2012).

Additional specimens examined

South Africa. WESTERN CAPE: 3420 (Bredasdorp): 18 km south by east of Buffeljachtsrivier (— BC), 21 Jun 1968, Acocks 23992 (NBG); Road heading due north of Malgas, east of Breede River (— BC), 3 Jun 2017, B. du Preez 289 (BOL), 291 (BOL, PRE), 10 Jul 2018, B. du Preez 514 (BOL, NBG, PRE); Napkysmond, near Now-I-Know farm (— BC), 11 Aug 2017, B. du Preez 319 (BOL, MO); 3 km west of Breede River mouth on south side of river along access road to Kontiki (— BD), 22 Feb 1981, C.J. Burgers 2633 Ex hort. (NBG); 8 Aug 2017, B. du Preez 310 (BOL, NBG, PRE); On slope, above and west, of harbour at Witsand (— BD), 16 Feb 2005, Euston-Brown 700 (NBG); Kloof NW of Mudlark Lodge (— BD), 10 Jul 2018, B. du Preez 512 (BOL, NBG, PRU).

Figures

Fig. 18. Composite plate of Polhillia pallens. 1 — Flower front view; 2 — Flower side view; 3 — Flower bottom view; 4 — Wing petal; 5 — Keel petal; 6 — Androecium; 7 — Gynoecium; 8 — Fruit; 9 — Close-up of leaf and stipules; 10 — Habit.Scale bars:4 mm.Photographs by B.du Preez

Fig. 6. Map showing distribution of Polhillia in the Western Cape Province, South Africa.A — Distribution of extra Overberg species; B — Species within and just outside of the Overberg region. Note expansion of square in A to map in B.