Kalanchoe olivierae Gideon F.Sm. & N.R.Crouch, sp. nov. (Figs 1 and 3–5)

Type:— SOUTH AFRICA. KwaZulu-Natal province. Central region of the province, 600 m above sea level [asl], 12 March 2025. Gideon F. Smith 1234 (holotype, Herb. PRU!).

[urn:lsid:ipni.org:names:77371027-1]

Diagnosis:— Kalanchoe olivierae differs from K. rotundifolia and K. steyniae in especially vegetative characters. Kalanchoe olivierae is usually weak- and single-stemmed and yet can grow very tall, and plants are sparse- and large-leaved. In contrast, K. rotundifolia and K. steyniae are small shrublets that often have their much smaller leaves ± densely arranged along stems that generally remain erect. The leaves of K. olivierae are very large, elliptic-ovate to somewhat spathulate, and on the adaxial surface guttered towards the base. In contrast, neither K. rotundifolia nor K. steyniae has a basally guttered adaxial leaf surface, and the leaves of K. rotundifolia are much smaller and nearly round to oblong-elliptic to elliptic-obovate while those of K. steyniae are elliptic-obovate. In addition, the leaves of K. olivierae are sparsely arranged, in contrast to those of K. rotundifolia that can be densely arranged and those of K. steyniae that are virtually always densely arranged. The flower morphology of K. olivierae (with uniformly pinkish orange corolla lobes) is similar to that of K. rotundifolia (with uniformly dull red to orange), but the bright crimson red flowers of K. steyniae, while also rotundifolioid, are much larger than those of both K. olivierae and K. rotundifolia, when measured from corolla lobe tip to opposite corolla lobe tip.

Description:—Biennial or generally short-lived perennial, few-leaved, generally unbranched, glabrous, medium-sized succulent, 200–500 mm tall, to 1.0(–1.2) m when in flower. Stems erect to leaning, remaining green, slowly turning light brown, rather herbaceous at maturity, 4–6 mm in diam. Leaves (30–)50–80(–90) × (25–) 30–40 mm, mid-green, opposite-decussate, sessile or with short petiole, erectly spreading or horizontally disposed, sparsely carried throughout; petiole ± absent or to 12(–15) mm long; blade succulent, sometimes flimsily so, elliptic-ovate to somewhat spathulate in outline, ± straight, ad- and abaxially ± flat, sometimes distally saucer-like upcurved; apex rounded-obtuse to slightly pointed; base cuneate, gradually tapering to insertion on stem, usually distinctly guttered towards stem; margins entire, concolorous, flared upwards in lower ⅓. Inflorescence a ± flat-topped, corymbose cyme, (200–)400–500(–850) mm tall, with small, widely dispersed, leaf-like bracts at nodes, bracts increasingly smaller upwards, floriferous only at top, erect or leaning, apically sparsely branched, many-flowered, branches opposite, subtended by small, leaf-like bracts, axis light green; pedicels 3–4(–6) mm long, robust, widening to base of flower. Flowers (10–) 12–14 mm long, erect; calyx uniformly light green, distinctly succulent; sepals 4, 1.0 × 1.0– 1.5 mm, ± separate, basally very slightly fused, ± triangular-deltoid, acute-tipped, cat claw-like clasping base of flower, hardly to slightly contrasting against basal part of corolla; corolla 11–13 mm long, basally substantially enlarged around carpels, distinctly and tightly anticlockwise-twisted apically after anthesis; corolla tube 9–12 mm long, pinkish orange throughout, light green basally at level of sepals, 4-angled, narrowly urceolate, globose basally, narrowing above carpels; corolla lobes 4–5 × 1.0– 1.5 mm, spreading at 60° angle, narrowly lanceolate, diurnal, uniformly pinkish orange, acutely tapering apically, margins slightly in-rolled in upper ½. Stamens inserted in two distinct ranks, one in middle of corolla tube, one higher up towards mouth of corolla tube, included; filaments 1.0– 1.5 mm long, thin, yellow; anthers 0.25–0.30 mm long, yellow. Pistil consisting of 4 carpels; carpels 4.0– 4.5 mm long, uniformly light green; styles 0.75–1.00 mm long, yellowish green; stigmas very slightly capitate, yellowish white; nectar scales 1.5–2.0 mm long, linear, light yellow. Follicles 4–5 mm long, light green at first, later whitish brown, enveloped in dry, light brownish white remains of corolla, eventually brittle, grass spikelet-like with remains of corolla then light brownish. Seed 0.50–0.75 mm long, dark brown, elliptic to clavate to almost deltoid-triangular, rough-surfaced. Chromosome number: unknown.

Distribution and habitat:—Except for the most general, no locality 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).

At present, K. olivierae is known to definitely only occur naturally in the eastern parts of the Eastern Cape adjacent to western KwaZulu-Natal, and in a broad near-coastal strip in KwaZulu-Natal, at elevations of 550–950 m asl, including in Scarp Forest (Foz 5) (Rutherford et al. 2006: 602–603).

Plants of K. olivierae almost invariably grow in the dense or dappled shade of a range of forest trees, shrubs, forbs, and grasses, often in thick humic layers of decaying leaves (Figs 3 and 5). Kalanchoes are well-known to colonise this type of habitat (Smith 2022).

Like some variants of K. rotundifolia, as well as for example the related K. krigeae, K. olivierae tends to be a biennial or often a short-lived perennial. The rapid accumulation of biomass to reach reproductive maturity within as short a space of time as possible and the subsequent production of flowers, nectar, fruit, and large volumes of seed derived from self- or cross-pollination seemingly weaken the plants and deplete them of the resources to subsequently initiate and sustain vegetative growth in further seasons. Under favourable environmental conditions, K. olivierae will however develop plants from the base, or higher up along the peduncle, in the axils of transitional bract-like leaves (Fig. 4).

Eponymy:— Kalanchoe olivierae is named for Dr Maria Catherina (‘Ria’) Olivier née Schoeman (16 July 1927 –) (Fig. 6). Ria was born on the farm ‘Lunsklip’ in the Swaershoek district between Somerset East and Cradock in the Eastern Cape province of South Africa. Up to Std 5 (present-day Grade 7) she attended a farm school, after which she received her secondary school education at the Bellevue Seminary for Girls in Somerset East that was established in 1882. Upon finishing school in 1944, Ria received the Croll Bursary to the value of £60.00, which partly enabled her to undertake graduate studies at Stellenbosch University in the Western Cape, from 1945 to 1947. In 1947 she graduated with a B.Sc. degree, majoring in botany and mathematics. From 1948 to 1949 Ria presented biology to medical students at the University of Cape Town (UCT) and in 1949 graduated with a M.Sc. degree from UCT; the topic of her Masters was the leaf epidermal structure of representatives of the Proteaceae. In 1966 a D.Sc. degree was conferred on her by the Stellenbosch University, for a study, under Prof. P. G. Jordaan (1913–1987), of the vegetation of the Worcester Nature Reserve, with her early collections mostly held at Herb. STE (Tölken 1971: 48, Gunn & Codd 1981: 266). In 1967 she accepted a permanent appointment as lecturer at the then University of Port Elizabeth (now Nelson Mandela University) in Gqeberha. Ria’s later collections are predominantly held in Herb. PEU (Smith & Willis 1999: 110, 151). She retired in 1987 and a few years later the University’s Herbarium was named for her. After retirement, Ria and her husband moved to Somerset West and five years later to Stellenbosch, where, at the ripe age of 98, she still lives. She is one of only a few women commemorated in the scientific name of a kalanchoe (Smith & Figueiredo 2023b: 222, 226–227).