Psoralea foliosa Oliv.

Leguminosae, B. Verdcourt. Flora Zambesiaca 3:6. 2000

Morphology General Habit

Branched erect shrub 1–3.5 m tall with densely pubescent branchlets.

Morphology Leaves

Leaves digitately 3-foliolate, mostly crowded; leaflets 7–35 × 2.5–14 mm, obovate to oblanceolate, acute, rounded or very slightly emarginate at the apex and recurved-mucronate, cuneate at the base, undulate, pubescent or glabrescent, densely gland-dotted, the glands smaller and more numerous on upper surface; petiole 1–2 mm long; petiolules c. 1 mm long; stipules 2–4 mm long, oblong-falcate.

Morphology Reproductive morphology Inflorescences

Inflorescences dense, subcapitate, mostly in uppermost axils and appearing terminal, comprised of 3–15 triplets of flowers; pedicels 2–3 mm long; bracts subtending each triplet 1.5–5 mm long, ovate or obovate, persistent, glandular, ciliate; bracts subtending flowers 1.5–3 mm long, linear to lanceolate.

Morphology Reproductive morphology Flowers Calyx

Calyx tube 3 mm long; lobes unequal, the lowest ± lanceolate, 6 mm long, the rest triangular-ovate, all pubescent and sparsely glandular.

Morphology Reproductive morphology Flowers Corolla

Standard white or pale blue with purple veins or darker purple centre, 9–10 × 7–8 mm with claw 1–3 mm long; wings longer than the keel, 9–10 × 2 mm with claws 2.5–3 mm long; keel purple with yellow glands at the tip, petals 6.5–10 × 2 with claws 3.5–4 mm long.

Morphology Reproductive morphology Flowers Androecium

Androecium 6–7 mm long, the vexillary filament lightly adherent.

Morphology Reproductive morphology Flowers Gynoecium Pistil

Ovary 1–2 mm long; stipe 1–1.5 mm long; style with straight part 3–5 mm long and apical upwardly curved part c. 1 mm long.

Morphology Reproductive morphology Fruits

Fruit 5–7 × 3–4 mm, papery, reticulate, puberulous.

Morphology Reproductive morphology Seeds

Seeds chestnut-brown to dark brown, 3.5–4.5 × 2.5–2.7 mm, oblong-reniform with central hilum.

Extinction risk predictions for the world's flowering plants to support their conservation (2024). Bachman, S.P., Brown, M.J.M., Leão, T.C.C., Lughadha, E.N., Walker, B.E. https://nph.onlinelibrary.wiley.com/doi/full/10.1111/nph.19592

Conservation

Predicted extinction risk: not threatened. Confidence: confident

International Legume Database and Information Service

Conservation

Not Threatened

Ecology

Africa: Afromontane grassland, Afromontane(upland) bushland and thicket.

Morphology General Habit

Perennial, Not climbing, Shrub

Stirton CH & Muasya AM. 2017. Ten new species and a new record for the genus Otholobium (Psoraleeae, Leguminosae) from South Africa. Kew Bulletin 72:50. DOI 10.1007/S12225-017-9722-5

Type

Type: Zimbabwe, Melsetter Distr., 20 Sept. 1906, Swynnerton 1417 (holotype BM!; isotype K!).

Morphology General Habit

Small densely leafy or tall virgate shrub up to 3 m tall

Morphology Branches

Branches silvery or tawny tomentose

Morphology Leaves

Leaves digitately trifoliolate, dense, or lax and spreading, petiolate, stipulate

Morphology Leaves Leaflets

Leaflets subequal, symmetrical; terminal lon­gest, 20 - 35 x 8 - 14 mm, obovate to oblong-obovate, rarely oblanceolate, recurved-mucronate, apex round­ed to emarginate, base cuneate, sparingly pubescent, glabrescent, glands of upper surface much smaller and more numerous than on lower surface, crateriform; petiole 1 - 2 mm long, petiolule < 1 mm long

Morphology Reproductive morphology Inflorescences

Inflorescences few to many in congested heads in upper axils of seasonal shoots, visible among leaflets; com­prised of 3 - 15 triplets on 2 mm long pedicel, each triplet subtended by a 1.5 - 2 mm long, cucullate, ovate or oblong, glandular, ciliate, persistent bract

Morphology Reproductive morphology Flowers

Flowers 8 - 9 mm long, pedicel 2 - 2.5 mm long; bract short, linear; mauve

Morphology Reproductive morphology Flowers Calyx

Calyx teeth subequal; carinal tooth longest, lanceolate, 6 mm long, other four teeth equal, triangu­lar, vexillary teeth not fused above the tube, tube 3 mm long; ribs prominent, teeth ciliate, sparsely pubescent with pellucid glad dots. Standard 9 x 7 mm, claw 3 mm long, oblong-ovate, emarginate, auriculate, mauve with white nectar guide, blade suffused with purple in mid area, veins purple

Morphology Reproductive morphology Flowers Corolla

Keel petals slightly fused to wing petals near auricles, 6.5 - 7 x 2 mm, claw 3.5 mm long Wing petals 9 x 2 mm, claw 3 mm long, auriculate, much larger than keel; sculpturing present, upper central, comprising up to 15 transcostal lamellae, rows indistinct

Morphology Reproductive morphology Flowers Androecium

Androecium 6 mm long, pseudomonadelphous, fenes­trate

Morphology Reproductive morphology Flowers Gynoecium Pistil

Pistil 6 mm long; ovary 1.5 mm long, stipitate, the stipe 1 mm long, sericeous, the hairs extending ⅓ along the style, entasis well-developed before the point of flexure, height of curvature 1.5 mm; stigma capitate, small

Morphology Reproductive morphology Fruits

Fruits 6 – 7 x 3.5- 4 mm, papery, weakly reticulate, pubescent

Morphology Reproductive morphology Seeds

Seeds 3.5 – 4 x 2.5- 2.7 mm, khaki to chestnut brown, hilum central

Note

Otholobium foliosum subsp. gazense is most commonly confused with O. wilmsii (Harms) C. H. Stirt. and differs in its sparsely glabrescent green leaflets with an equal number of glands on both surfaces (vs sparsely sericeous glaucous leaflets with more glands on upper surface),lanceolate stipules (vs linear),shortly pedunculate inflorescences congested within subtending leaves (vs long pedunculate inflorescences over-topping the subtending leaves), rounded apex of the keel petals (vs beaked keel petals), and the asymmetric oblanceolate (vs broadly oblong) fruits. Only Otholobium foliosum subsp. gazense occurs in Southern Africa. It is separated from O. foliosum subsp. foliosumby its larger, 20 - 35 x 8 - 14 mm, obovate to oblong-obovate, rarely oblanceolate leaves (vs 7 - 17 x 2.5 - 4.5 mm, oblanceolate leaves), vexillary and lateral calyx teeth equal (vs subequal and longer vexillary teeth), calyx pale green with purple ribs (vs green without purple ribs), ovary finely pubescent with black hairs (vs sericeous), fruit surface weakly reticulate to almost smooth (vs strongly retic­ulate) and seeds khaki to chestnut brown (vs tan to dark brown). The subspecies is rather variable in its southern African distribution and two groups require further study in the field. Group A is centred in the Limpopo area of South Africa and occurs in the Blaauberg, Houtbosch, Kratzenstein, Mohlakeng Pla­teau and on the Soutpansberg. This group is characterised as follows: taller virgate shrubs with leaves with rounded apices, violet-purple flowers, even-sized, prominent, raised, nigro-punctate glands, calyces silvery with the carinal teeth much longer than the other four teeth, and khaki-coloured seeds. Typical specimens are: Breyer s.n. (PRE 55393); Codd & Dyer 9149, Esterhuysen 21418, Gillett 2906, Grobbelaar2906, Hemm 587, Hoffman 120, Pole Evans 909, Rehmann 6268, Rodin 4068, Strey 7993, Van Niekerk 2906. Group B occurs in Eastern Zimbabwe and Northern South Africa. In South Africa it is centred near Haenertsburg, Magoebaskloof, New Agatha, The Downs and on the southern slopes of the Soutpansberg Mountains and the Mpumalanga Drakensberg Mountains. In Zimbabwe it is found at Melsetter, Glencoe Forest Reserve, Stonehenge and in the Chimanimani Mountains. This group is represented by bushier plants with more compact purple-flowered inflorescences, shorter calyces, deeper sunken glands, and khaki-coloured seeds. The leaves dry a much darker colour than those of Group A and the leaflets are less rounded, hairy on both surfaces and have more sunken glands. The plants are taller, more open- branched shrubs. This group is somewhat intermediate between O. foliosum subsp. gazense and O. wilmsii. The carinal tooth is very distinct in bud. Typical specimens are: Codd 8420, Drummond 4999, Drummond & Phipps 288, Goodier 212, Marais 76, McCallum s.n. (PRE 55339), Meeuse 9779,Scheeperss.n., and Strey 1886.

Distribution

Africa: South Africa, Limpopo and Mpumalanga; Eastern Zimbabwe.

Ecology

Within and at the edges of forested gullies in montane grasslands, and along stream banks at altitudes between 1000 – 2500 m. It occupies similar habitats to Otholobium caffrum, O. wilmsii, O. foliosum and O. fumeum and may become quite invasive in disturbed areas such as firebreaks.

Conservation

Under the IUCN Conservation status criteria, this species is listed as Least Concern (LC, Raimondo et al. 2009). The Rabinowitz Rarity Code is WAB (widespread, abundant, broad); abundant and widespread over a large range across several habitats and vegetation types. This species regrows from seed after fire, and its seed production is prolific.

Phenology

Flowering may take place all year round. There are, however, distinct peaks of flowering in January, February, July and December