Crassula turpiniae N.R.Crouch, Mich.Walters, M.Lötter & Gideon F.Sm., 2025

Crassula turpiniae N.R.Crouch, Mich.Walters, M.Lötter & Gideon F.Sm. , sp. nov. ( Figs 1 View FIGURE 1 and 2 View FIGURE 2 ).

Type:— SOUTH AFRICA. Mpumalanga province: Lydenburg District (2530 BA), on rock ledges in montane grassland, elev. 1700 m, 8 November 2006, J. E. Burrows 9562 ( holotype, Herb. BNRH [now incorporated into Herb. J]!).

Diagnosis:— Crassula turpiniae most closely resembles C. multicava and C. ovata . It differs from C. multicava in its smaller and more rotund leaves with hydathodes present in a single row along the leaf blade margins rather than widely scattered over both surfaces; in its stems that are much more prominently constricted at the nodes; and in the longer pedicels of its flowers, which at anthesis have white rather than red-infused petals. Crassula turpiniae differs from C. ovata in its leaf shape, which sports a mostly rounded rather than pointed or mucronate apex; in its smaller and more prostrate habit, and in having calyx lobes that extend over a greater proportion (to ½) of the corolla than in C. ovata (to ⅕).

Description:—Perennial, ± branched, succulent plants. Roots thickly succulent, occasionally caudiciform. Stems carnose, lower down up to 10 mm in diam.; bark greyish brown, flaking. Branches 0.25(–0.70) m long, often patent, succulent to slightly woody, glabrous, spreading to procumbent to pendulous, prominently constricted at nodes where they sometimes root. Leaves dorsiventrally flattened, glabrous, glands occasionally scattered ad- and abaxially, green-blue, turning red before abscission, desiccating leaves deciduous, petiolate; blade (15–)20–22(–28) × (17–)18–19(– 27) mm, broadly ovate to suborbicular, basally rounded; margin entire to repand, green-blue or reddish, glands in an uneven row; apex rounded to obtuse to truncate; petiole 2–3 mm long. Inflorescence sympodial, an irregularly branched, terminal, compound dichasium, subumbellate, 17–30 × 1.2–1.5 mm; peduncle distinct, deep pink, bracts narrowly oblong; pedicels 9–11 × 0.4–1.2 mm, glabrous, tapering towards base, reddish proximally, green distally. Flowers pentamerous, rarely hexamerous. Calyx lobes 1.6–2.0 × 0.4 mm, oblong, acute to truncate, glabrous, fleshy, green with red apex, ± ½ as long as petals. Corolla star-shaped, scarcely fused at base, white; petals 3.5–4.0 × 1.5 mm, spreading at right angles to pedicel to slightly recurved, ovate-elliptic, broadly acute, with the terminal hood pink below, without prominent dorsal appendage. Carpels oblong-reniform; ovary 1.5 × 0.8 mm, white, turning cherry red; ovules 4–5(–7), elongate, with rows of pointed papillae; style 1 mm long, slender, arising from posterior ovary wall, stigma indistinct. Stamens with filaments 2.5 mm long; anthers 0.3–0.4 mm long, purple-brown; pollen yellow-cream. Squamulae as long as broad, constricted towards base, 0.3 × 0.3 mm, yellow, apically indented, slightly recurved. Seeds 0.45 × 0.25 mm, ellipsoid, brown, with vertical rows of papillae. Chromosome number: unknown.

Distribution and habitat:— Crassula turpiniae is endemic to the Mpumalanga province of South Africa where it has only been recorded from the Lydenburg–Pilgrim’s Rest region. Except for this general locality (see Fig. 3 View FIGURE 3 ), no provenance data from specimens or field observations are given. This deviation from widely followed taxonomic practice is justified by the fact that illegal collecting of succulent plants from the wild in South Africa is a severe and escalating problem, and it was decided not to provide any information regarding the exact whereabouts of this new species that could cause known populations to be targeted for destructive collecting ( Smith et al. 2023).

Plants of Crassula turpiniae are near-obligate cremnophytic. The species is currently only known from four localities although we anticipate the occurrence of several other, as yet undiscovered populations, because of the inaccessibility of the terrain.

The species occupies a narrow ecological niche on fire-protected cliffs. In habitat, plants are scattered or clustered across suitable sites and may be locally abundant as at the type locality where the population comprises over 100 individuals, most of which form spreading colonies. The species extends over a range of 50 km in a narrow north–south band where it straddles steep southern, southeastern, and eastern slopes in Long Tom Pass Montane Grassland ( Lötter & Burrows 2012). It grows at an elevation of 1640 to 2200 m above sea level, usually in places in partial sun, which receive sunlight in the morning only, and always in fire protected microhabitats on or near rocks. Plants sometimes occur in the partial shade of rock overhangs or shrubs. This known range is frequently covered in mist and receives between 980 and 1290 mm of rainfall every year, based on a 2020 high-resolution rainfall model developed by the Mpumalanga Tourism & Parks Agency. At these high altitudes, the temperature is quite cool with a modelled average annual temperature of only 14 to 16° C ( Schulze 1997). The geology is comprised of banded shale and quartzites of the Timeball Hill and Hekpoort formations of the Pretoria Group, where plants tend to grow in small pockets of humus rich soils scattered in the narrow crevices between shale and quartzite rock layers ( Fig. 1C View FIGURE 1 ). These steep and rocky areas are generally protected from fires and such shielded plants may grow to become compact and cushion-like ( Fig. 1E View FIGURE 1 ). Associated plant species include Merwilla plumbea ( Lindley 1830: 1355) Speta (1998: 109) , Helichrysum reflexum Brown (1894: 356) , Schizochilus lilacinus Schelpe ex Linder (1980: 426) , Selaginella mittenii Baker (1883: 81) , and Streptocarpus galpinii Hooker (1891: 388) .

Phenology:—Plants flower from September to November, peaking in October.

Etymology:— Crassula turpiniae is named in honour of Ms Barbara Turpin ( 7 June 1959 –) for her valuable contribution to plant conservation in the Mpumalanga province, South Africa. On first arrival in South Africa from England some 20 years ago, she spent several years as a volunteer digitising and georeferencing thousands of herbarium specimens for the Lydenburg (Herb. LYD), Buffelskloof (Herb. BNRH [now incorporated into Herb. J]), and Hortus Siccus McMurtrianus (HSMC) herbaria. Ms Turpin was based at the Buffelskloof Herbarium until January 2021 and remained actively involved in plant collection, documentation, and conservation in Mpumalanga in South Africa, and in Mozambique. In 2017 Ms Turpin accompanied the authors to the type locality to assess the population of the species subsequently named for her.

Conservation status:— Crassula turpiniae is one of more than 50 plant species that are endemic on the shale- or quartz-derived substrates of the Lydenburg Centre of Plant Endemism ( Lötter et al. 2002). The Lydenburg Centre occupies the region between the Wolkberg Centre to the East and the Sekhukhuneland Centre to the northwest and its geology predominantly consists of shale, quartzite, and small quantities of andesite, with diabase intrusions. Two subcentres have been identified within the Lydenburg Centre, namely the Long Tom Pass- (21 endemics) and Steenkampsberg- (16 endemics) subcentres, with most of the endemics found in the families Iridaceae , Orchidaceae , Asteraceae , Gesneriaceae , and Ericaceae . Although only 60% of the Long Tom Montane Grassland is still natural and untransformed ( Lötter et al. 2014), all of the known populations of C. turpiniae occur within gazetted protected areas. Threats to this area are primarily from invasive alien plants or from both organised and illegal artisanal gold mining activities ( Lötter & Burrows 2012), although plants could potentially be poached for the illegal trade in such subjects. The Lydenburg Centre is included within the recently defined orographic entity, the Limpopo–Mpumalanga– Eswatini Escarpment ( LMEE), itself a component of southern Arica’s Great Escarpment ( Clark et al. 2022). The presence of C. turpiniae as endemic to the LMEE further reinforces the circumscription of this newly recognised orographic entity, which is likely the largest in the summer rainfall region of southern Africa.

Crassula turpiniae has a very small extent of occurrence of < 20 km 2 and fewer than five known locations. The threat to subpopulations of alien plants through encroachment by trees of the genus Pinus is substantial and expanding continuously, with many cliffs in nearby gorges completely colonized by pines; these are spreading with little or no control. We accordingly propose a national Red List category of Near Threatened.

Additional collections ( paratypes):— SOUTH AFRICA. Mpumalanga province: Lydenburg District (2530 BA), wooded grassland, 14 September 2010, H. Delhay 229 ( BNRH [now incorporated into Herb. J]!) ; elev. 1730 m, 7 November 2017, N. R. Crouch, M. Lötter & B. Turpin 1293 ( BNRH [now incorporated into Herb. J]!) ; 29 January 2014, D. M. McMurtry 15209 ( BNRH [now incorporated into Herb. J]!) .