Psoralea crista C. H. Stirt. & Muasya, 2024

Stirton, Charles H., Bello, Abubakar & Muasya, A. Muthama, 2024, Ten new species and notes on the genus Psoralea L. (Psoraleeae, Fabaceae) from South Africa, Plant Ecology and Evolution 157 (3), pp. 291-312 : 291-312

9. Psoralea crista C. H. Stirt. & Muasya sp. nov.

Figs 2 , 12

Psoralea sp. 14 (“ Psoralea crista C. H. Stirt. ms. ”, nom. nud.), Stirton and Schutte (2012: 574)

Psoralea sp. D ( ‘ crista ’) Stirton (2019: 1038)

Type.

SOUTH AFRICA – Eastern Cape Province: 3324 (Steytlerville) • Great Wintershoek Mountains, Cockscomb ; 2 Feb. 1958; Esterhuysen 27531; holotype: PRE; isotype: BOL .

Diagnosis.

Species similar to Psoralea keetii Schönland ex H. M. L. Forbes from which it differs in its low shrubby habit ( P. keetii erect robust shrub up to 2 m tall); leaflets drooping, small, not fleshy, 7–13 × 2.5–4.5 mm, elliptic, flat, with symmetrical lateral leaflets ( P. keetii leaflets large, displayed, fleshy, 20–26 × 7.5–11.0 mm, narrowly obovate to obovate, laterals asymmetrical); flowers 8–9 mm long, blue, solitary, borne on long green pedicels ( P. keetii flowers 10–11 mm long, dark mauve to blue with darker blue nectar guide, borne on long purple pedicels); cupulum distinctly trifid, lobes toothed ( P. keetii cupulum scarcely developed, lobes rounded); calyx teeth green, teeth equal, shorter than the tube ( P. keetii calyx teeth purple, teeth subequal, shorter than the tube).

Description.

Low glabrous shrublet up to 50 cm tall. Stems glabrous, green, slender, terete, finely ridged, covered in variously sized glands. Leaves pinnately trifoliolate, stipulate, densely covered in glands drying black. Leaflets 7–13 × 2.5–4.5 mm, flat, elliptic, apex mucronate, base cuneate, laterals smaller, symmetrical; petioles 4–7 mm long, channelled. Stipules 2.0–3.1 (– 3.5) × 0.5–1.0 mm, fused at base, adnate to petiole in lower part, broadly triangular and narrowing further up the stem. Inflorescences reduced to a solitary flower, axillary, produced on short lateral shoots. Flowers 8–9 mm long, blue; cupulum shortly trifid, tube 1 mm deep, keel lobe 1.7 mm long, laterals 1.4 mm long; inner face of teeth finely covered in black stubby hairs, densely glandular. Calyx 6 mm long, teeth equal, carinal tooth symmetrical, obtuse, other four asymmetrical, falcate, acute; tube 3.5 mm deep; inner face of teeth covered in short appressed black hairs, externally densely encrusted with raised glands, evenly on teeth and tube. Standard petals 9–10 × 8–9 mm; claw 1.5 mm long; broadly obovate, weakly auriculate, appendages well-developed, free from auricles; apex truncate. Wing petals 7 × 3 mm, sharply upcurved; auricle well-developed; sculpturing upper basal with 4–7 transcostal lamellae, shortening towards the middle axis of the blade. Keel petals 9 × 3 mm, 3.5 mm high from claw axis; claw 4.5 mm long; apex rounded, slightly beaked below apex. Androecium 9 × 2 mm, vexillary stamen free. Pistil 9 mm long, ovary 1.3–1.5 mm, glabrous; gynophore present, 0.5 mm long; style glabrous, thickened at point of flexure, height of curvature 3.5 mm, stigma capitate, finely penicillate. Fruits and seeds unknown.

Distribution and habitat.

Psoralea crista is a rare mountain endemic known from only two collections from Cockscomb Peak in the Great Wintershoek Mountains (Fig. 2 ) in Kouga Sandstone Fynbos (FFs 28) and Kouga Grassy Sandstone Fynbos (FFs 29) ( Mucina and Rutherford 2006). It was first collected 35 years ago by Miss Elsie Esterhuysen. A second collection was made in the same general locality in 2008 by Nick Helme. The species prefers slightly damp areas or seasonal seepages on NE and E slopes below cliffs at ca 1400–1600 m a. s. l.

Phenology and ecology.

Flowering occurs in January and February, fruiting up to May. No recent collections have been made of this species and no photographs are available.

Etymology.

The specific epithet crista (Latin word ‘ crista’ = crest or terminal tuft) alludes to the fleshy stipules reminiscent of a rooster’s fleshy cockscomb and the name of the Cockscomb Mountain where it occurs.

Preliminary IUCN conservation assessment.

This species is probably highly localised on a single mountain. Recent attempts by the High-Altitude Group of CREW (Custodians of Rare and Endangered Wild Flowers) have so far been unable to find it. It may be a resprouter and fire-dependent, likely to be prevalent after episodic fire, and preliminary assessed as Data Deficient (DD).

Additional material examined.

SOUTH AFRICA – Eastern Cape Province: 3324 (Steytlerville) • Cockscomb Peak East, farm Afgunst 255 , peak near cave (– DB); 31 May 2008; Helme 5478; NBG .

Figures

Figure 2. Known distribution of the ten described Psoralea species. Map by Abubakar Bello.

Figure 12. Psoralea crista. A. Flowering shoots. B. Leaflet. C. Transverse section of petiole. D. Stipule. E. Pedicel. F. Cupulum at tip of pedicel. G. Leaf position. H. Side view of a flower. I. Standard petal opened out. J. Side view of standard petal. K. Wing petal. L. Keel. M. Calyx opened out showing inner face and black stubby hairs on inner face of teeth. N. Pistil. O. Stigma. P. Apex of terminal leaf. Artist: Angela Beaumont.