Psoralea schutteae C. H. Stirt., 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

1. Psoralea schutteae C. H. Stirt. sp. nov.

Figs 1 , 2

Type.

SOUTH AFRICA – Western Cape Province: 3322 (Oudtshoorn) • Road from Cango Caves to Prince Albert (– AC); 33 ° 23 ’ 51.9 ” S, 22 ° 11 ’ 37.18 ” E; 11 Nov. 1986; Stirton & Žantovská 11565; holotype: NBG; isotype: PRE .

Diagnosis.

Psoralea schutteae has been included in Psoralea candicans Eckl. & Zeyh. but is distinguished by its densely branched compact spreading habit ( P. candicans an erect laxly branched shrub up to 1.5 m tall with long virgate spreading branches); leaflets 8–9 × 2–4 mm, glands visible when fresh, drying reddish brown ( P. candicans leaflets 10–20 × 3–4 (– 6) mm, glands scarcely visible when fresh but drying orange-red); flowers 5–6 mm long, stumpy in appearance, bracteate, bracts 2 mm long ( P. candicans flowers 7–10 mm long, ebracteate or minute); standard petal scarcely reflexed, dull white to pale lilac, nectar patch reddish violet but scarcely visible from the front ( P. candicans standard petal bright white, nectar patch purplish, triangular, and violet flecked with white, and tapering towards apex); calyx teeth as long or slightly longer than the tube, equal, incurving, narrowly triangular with broad base, acute, teeth 3–4 × 0.5 mm, tube not constricted in middle, not suffused with purple ( P. candicans calyx teeth 2–3 times longer than tube, subequal, slightly falcate to straight, linear-lanceolate, taper-pointed, teeth 4–8 × 1 mm, tube strongly constricted in middle, suffused with purple); fruiting calyx scarcely longer than the largely exposed fruit ( P. candicans fruiting calyx 2–3 times longer than the fruit).

Description.

Small rounded compact shrub up to 60 cm tall, facultative-reseeder. Stem branches numerous, dense, greyish brown, rough; young seasonal shoots canescent, laxly leafy, otherwise leaves smaller and overlapping in older plants. Leaves digitately trifoliolate, petiolate. Leaflets 8–9 × 2.0–4.0 mm, narrowly obovate to obovate (basal ones of shoot), recurved mucronate, mucro short straight to slightly hooked, apex emarginate, base cuneate; conduplicate, flatter in younger leaflets; stiff, veins prominent, glands visible when fresh, drying reddish brown, surfaces sparsely pubescent, thicker along margins and on veins; surfaces nitid, dark green; petiole 1.0–2.0 mm long; petiolules 0.5 mm long. Stipules 1–2 mm long, broadly subulate, fused to lower third of petiole, semi-patent, rapidly senescent, persistent. Inflorescences axillary, sessile; comprised of 1 triplet of distinctly pedicellate flowers, each triplet bracteate, triplet bract oblong up to 2 mm long, canescent. Flowers 5–6 mm long, white; bracteate, bract narrowly oblong up to 2 mm long; pedicel up to 1 mm long. Calyx teeth as long or slightly longer than the tube, equal, incurving, narrowly triangular with broad base, acute, lobes 3–4 × 0.5 mm, vexillar lobes scarcely fused above the tube; appressed hairy, glands evenly dispersed on teeth and tube; characteristically strongly accrescent in fruit, lobes erect, caging the clearly visible pod, veins ridged and prominent. Standard petals 6 × 6 mm, whole blade not folded tightly backwards but scarcely reflexed, dull white to pale lilac, nectar patch reddish violet but scarcely visible from the front, apex broadly emarginate; claw narrow, 3 × 1 mm, auricles scarcely developed. Wing petals longer than keel petals but not attached, 6.0 × 1 mm, claw 2 mm long; blade billowy, hiding the keel, distal portion folded downwards; sculpturing upper basal and upper left central, comprising up to 20 transcostal lamellae, becoming smaller towards the centre, auricle swollen and rough; claw 2 mm long. Keel petals 3.5–4.0 mm long, blade 2.0 × 1 mm, apex acute, most of blade purple with darker veins; claw 3 mm long. Androecium 4 mm long, pseudomonadelphous, non-fenestrate. Pistil 4.0 mm long; ovary 1.3 mm long, shaggy; height of curvature 1.2 mm, entasis well-developed at point of flexure, style glabrous, forward sloping; stigma capitate, penicillate. Fruits 3 × 2 mm, obliquely obovate, papery, finely pubescent, distinctly reticulate. Seeds 3 × 2.3 mm, chestnut brown, hilum round, subcentral.

Distribution and habitat.

Psoralea schutteae is a widespread species ranging from the Tulbagh region though Montagu to the Groot Swartberg mountain range (Fig. 2 ) occurring predominantly in Kango Limestone Renosterveld (FRI 1) but also in Swartberg Shale Renosterveld (FRS 15) but also other types of renosterveld and renosterveld – fynbos transitions. It is a facultative-reseeder setting copious seed but once established sprouts commonly after burns. It occurs between 550 and 750 m a. s. l.

Phenology and ecology.

Flowering takes place in October and fruiting in November.

Etymology.

The species is named in honour of the taxonomist and conservationist Dr Annelise Schutte-Vlok who has contributed significantly to modern revisions of the Cape genera of the tribe Podalyrieae ( Fabaceae ).

Preliminary IUCN conservation assessment.

No assessment has been made of this species. As most of the known collections have been made along roadsides, they are now very threatened by roadside works. Few collections have been made beyond such localities so it should be looked for in remaining vegetation away from roads. However, as it is widespread and commonly colonial, it is preliminary considered as Least Concern: LC.

Additional material examined.

SOUTH AFRICA – Western Cape Province: 3319 (Worcester) • Tulbagh (– AC); Ecklon s. n.; MEL [ MEL 1542103 ], NBG [ SAM 15414 ] • Nuwekloof Pass (– AC); 30 Nov. 2007; Muasya & Stirton 3369; BOL • Nuwekloof Pass (– AC); 18 Oct. 1941; Barker 2374; NBG • Cogmanskloof dam, Kanetvlei (– AD); 1 Jan. 2008; Muasya & Stirton 3559; BOL • Along roadside near Karoo Poort (– BA); 29 Nov. 1908; Pearson 4805; BOL, K, NBG • Hex River Valley near De Doorns (– BC); 30 Oct. 1974; Goldblatt 3203; BR, MO • Hex River Valley, De Doorns (– BC); 1 Oct. 1893; Bolus 8005; NBG • Hex River ; 1 Oct. 1983; Bolus 3056; NBG • Hex River East ; Oct. 1893; Tyson 3104; SAM • Between Hottentots Kloof and Karoo Poort (– BC); 29 Nov. 1908; Pearson 4811; K • Bokkeveld Flats (– BC); Oct. 1923; M. Levyns & J. Levyns 527; NBG • 27.5 km from Worcester to Villiersdorp (– BD); 30 Nov. 2011; Muasya & Stirton 3911; BOL • Rabiesberg, Worcester (– CA); 26 Sep. 1935; Compton 5823; BOL, NBG • ibid.; 27 Sep. 1935; Lewis s. n.; BOL [ BOL 32219 ] • Karoo Gardens (– CB); 26 Sep. 1953; Compton 24365; NBG • Karoo Gardens (– CB); Jan. 1977; Perry 24; NBG • Worcester (– CB); 28 Oct. 1948; Liebenberg 4200; PRE • Worcester (– CB); 14 Nov. 1962; Olivier 207; PRE • Langeberge, Robertson (– DB); Nel s. n.; NBG [ NBG 254651 ] • Karoo Koppie, Robertson (– DD); Sep. 1934; Kuum s. n.; NBG [ NBG 254655 ] • 3320 (Montagu): Lower Gannaga Pass , Tanqua National Park (– AA); 19 Sep. 2008; Rosch 601; NBG • 22 km from Montagu to Barrydale (– CA); 26 Oct. 1986; Stirton & Žantovská 11283; K, NBG • Klipbokkraal (– CC); 26 Oct. 1961; Van Breda 1494; PRE • Warmwaterberg (– CD); 1 Jan. 2008; Muasya & Stirton 3563; BOL • 2 km S of Bonnievale on road to Stormsvlei (– CD); 29 Jul. 1988; Bean & Viviers 2029; BOL, NBG • 55 km from Montagu to Barrydale (– CD); 26 Oct. 1986; Stirton & Žantovská 11282; K, NBG • Anysberg Mountain, near farm Touwsfontein (– DA); 31 Dec. 1986; Vlok 1823; PRE • Ruggens, Zuurbraaks (– DC); 11 Sep. 1897; Galpin 3960; PRE • Near start of the Barrydale Hiking Trail (– DC); 22 Aug. 2015; Du Preez 102; BOL • 3321 (Ladismith): on top of pass to Gamkaskloof , Swartberg Mountains (– BC); 2 Oct. 1986; Vlok 1632; NBG, NU, PRE • In Karoo near Gauritzrivier (– DC); Zeyher s. n.; K, S, SAM, W . – 3322 (Oudtshoorn) • Swartberg Pass (– AC); 12 Dec. 1981; Stirton 10332; K, NBG, PRE • Swartberg Pass (– AC); Stirton 11565; K, NBG • Between Kliphuisvlei and Die Hell (– AC); 2 Mar. 1986; Goldblatt 7993; MO • Foot of Swartberg Pass on road to Oudtshoorn (– AC); 4 Oct. 1974; Goldblatt 1974; NBG • 3 km from Cango caves on Oudshoorn – Prince Albert Road (– AC); 1 Jan. 2008; Muasya & Stirton 3575; BOL • Rus-en-Vrede (– AC); 12 Dec. 1981; Stirton 10332; BOL, K, NBG, PRE • Rus-en-Vrede (– AD); 28 Sep. 2010; Muasya & Stirton 5587; BOL • Swartberg Pass, near Forester’s House (– CC); 11 Dec. 1981; Stirton 10321; K, NBG, PRE . – 3420 (Bredasdorp) • Van Rheenen’s Crest farm, above Dam, nr. Heidelberg (– AA); 25 Nov. 2011; Stirton & Muasya 13544; BOL .

Figures

Figure 1. Psoralea schutteae. A. Resprouting shrub with lateral seasonal shoots. B. Rounded shrub. C. Axillary triplet of flowers and leaf. D. Shoot with seasonal branches. E. Infructescences with short-lobed calyces showing exposed fruits. F. Leaves and flowers. Photographs by Charles Stirton.

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