Kalanchoe krigeae Gideon F.Sm. & Figueiredo, 2023

Smith, Gideon F. & Figueiredo, Estrela, 2023, Kalanchoe krigeae (K. subg. Kalanchoe; Crassulaceae subfam. Kalanchooideae), a new, small-growing species from northeastern South Africa split off from K. rotundifolia, Phytotaxa 603 (3), pp. 280-288 : 284-285

Kalanchoe krigeae Gideon F.Sm. & Figueiredo , sp. nov. ( Fig. 2A–E ).

Type:— SOUTH AFRICA. Mpumalanga province.—2430 (Pilgrim’s Rest): near Pilgrim’s Rest, towards Bourke’s Luck (– DB), in rocky patches in savanna, ca. 1100 m above sea level [asl]. 12 May 2023. Gideon F. Smith 1207 (holotype PRU) .

Diagnosis:—The overall colour of the leaves and stems of K. krigeae is light green to very light glaucous, while those of K. rotundifolia are glaucous to dull light yellowish green, and those of K. decumbens are generally uniformly light green. Leaves of K. krigeae and K. rotundifolia are firm while those of K. decumbens are soft-textured. Kalanchoe krigeae has lanceolate-cymbiform to narrowly oblong-terete leaves while those of K. decumbens are narrowly oblong to somewhat clavate, and those of K. rotundifolia are round to oblanceolate to obovate. The adaxial surface of the corolla lobes of K. krigeae is uniformly apricot-orange to bright orange to red to sometimes orange-infused, that of K. decumbens is uniformly vividly deep red to orange-red, and that of K. rotundifolia is uniformly red to dull orange.

Description:—Annual, perennial, or biennial, few-leaved, unbranched or sparsely branched from base, glabrous, low-growing, small succulent, with erect to leaning to creeping stems, 5–15(–30) cm tall when not in flower. Stems one to few arising from the rootstock or slightly higher up, light green, bluish purple-infusion lacking, usually simple or sometimes producing obovate-leaved branchlets near base, main stems very rarely branched higher up, thin, ± herbaceous. Leaves (15–)20–45(–50) × (5–) 6–8 mm, light green to very light glaucous, with slight bloom, generally not finely purple-dotted except when young, opposite-decussate, sessile, erectly spreading at a 30–45° degree angle, sparsely carried throughout; petiole absent; blade succulent, obovate when young, lanceolate-cymbiform to narrowly oblong-terete at maturity, often involute, then appearing channelled above, usually straight; apex rounded-obtuse or slightly pointed; base gradually tapering to a narrow insertion on the stem; margins entire. Inflorescence a corymbose cyme, (5–)10–30(–35) cm tall, with leaf-like bracts at nodes, bracts increasingly smaller upwards, floriferous only at the top, erect or leaning, apically sparsely branched, 1- to few- to several-flowered, branches opposite or sometimes with only a single branch at a node, subtended by small, persistent leaf-like bracts, leafy branchlets rarely developing in axils, axis light green, generally lacking slight waxy bloom; pedicels slender, 4–6(–18) mm long. Flowers 12–14 mm long, erect; calyx dull green, distally reddish-infused, covered with slight bloom; sepals 4, ± 1.00 × 0.75–1.00 mm, ± separate, basally very slightly fused, deltoid-triangular, often blunt-tipped to rounded-acute, hardly to slightly contrasting against basal part of corolla; corolla 11–13 mm long, prominently enlarged basally around carpels, distinctly and tightly anti-clockwise-twisted apically after anthesis; corolla tube 10–12 mm long, distally consistently dull orangegreen, bluish purple infusion lacking, more strongly green-infused around ovaries, light green basally at level of sepals, 4-angled, narrowly urceolate, strongly globose basally to 4-angled when viewed from below, narrowing above carpels; lobes 5–6 × 1.5–2.0 mm, spreading at 45–90° angle to sigmoidally down- and upcurved, usually uniformly apricot-orange to bright orange to red, if red, sometimes orange-infused, slight yellowish-infusion in centre generally lacking, narrowly elliptic, rounded-acute to acute apically, then minutely apiculate, margins apically in-rolled, showing diurnal movement. Stamens inserted in two ranks near mouth of corolla tube, included; filaments 1–2 mm long, thin, yellow; anthers 0.25–0.30 mm long, yellow. Pistil consisting of 4 carpels; carpels ± 5 mm long, uniformly mid-green, distinct purple-infusion lacking; styles 0.75–1.00 mm long, yellowish green; stigmas very slightly capitate, yellowish green; scales 2.0– 2.5 mm long, linear, light yellow. Follicles 5–8 mm long, light green at first, enveloped in dry, whitish remains of corolla, eventually brittle, grass spikelet-like with remains of corolla then light brownish white. Seed 0.50–0.75 mm long, very faintly striated, ellipsoid to more rarely somewhat banana-shaped, dark brown. Chromosome number: unknown.

Distribution and habitat:— Kalanchoe krigeae occurs naturally in the vicinity of Pilgrim’s Rest and Bourke’s Luck in northeastern Mpumalanga at an elevation of 1000–1100 m asl, with its distribution range petering out further south in the direction of Mbombela and Eswatini, and unconfirmed reports also places it further north. In contrast, K. decumbens is restricted to the southeastern border area between Eswatini, the northeastern parts of South Africa’s KwaZulu-Natal province, and possibly also occurs in adjacent southwestern Mozambique, at an elevation of only about 600 m asl. Kalanchoe rotundifolia occurs sympatrically with both K. decumbens and K. krigeae and is widely dispersed in an extensive natural geographical distribution range through eastern-southern and south-tropical Africa, further north to eastern Africa and the Indian Ocean island of Socotra.

Plants of K. krigeae grow in the dappled shade of a range of different grasses, shrubs, and (often deciduous) trees, often in thin soils that accumulate in depressions in rock sheets. Virtually the entire known natural geographical distribution range of K. krigeae , much of it along the northern Drakensberg escarpment, falls within the Wolkberg Centre of Endemism, to which it accordingly is near-endemic ( Van Wyk & Smith 2001: 120–125). At least two other kalanchoes, K. winteri Gideon F.Sm., N.R.Crouch & Mich.Walters in Crouch et al. (2016: 219) and K. crouchii Smith & Figueiredo (2018b: 87) , are endemic to the Wolkberg Centre of Endemism. The natural geographical distribution range of K. krigeae additionally overlaps with that of K. sexangularis Brown (1913: 120) . Although these species to a large extent flower simultaneously during the winter months, hybrids or intermediate forms have yet to be observed. Tölken (1985: 62–64, Fig. 7), when discussing and illustrating forms of a broadly conceived K. rotundifolia , noted material here described as K. krigeae under his Figure 7(c).

At species rank, Kalanchoe is most diverse in Madagascar, but with significant secondary centres of high species diversity present in southern, southwestern south-tropical, and eastern Africa.As the genus is presently understood, the number of species indigenous to the Near, Middle, and Far East are much lower than in Madagascar and Africa. The largest diversity of southern African Kalanchoe species is found in eastern southern Africa where 22 of the indigenous subcontinental species occur east of the Drakensberg massif, from south-central KwaZulu-Natal in the south in a broad sweep to the Limpopo River in the north (Smith & Figueiredo 2021: 207–208, Smith 2022a: 164–167).

Eponymy:— Kalanchoe krigeae is named for Alicia Krige (born Welkom, Orange Free State [now the Free State] province, South Africa, 26 June 1982 –) ( Fig. 2F ). Alicia graduated from the University of Pretoria with a B.Sc. degree in 2004 and a B.Sc. (Hons) degree in 2005, both specialising in Botany. Her B.Sc. (Hons) project involved a study of the silver vegetation at the interface of the grassland and savanna (bushveld) biomes in the Broederstroom area, Gauteng province, South Africa (see Krige & Van Wyk 2005). In 2012 Alicia was awarded a M.Sc. degree, also by the University of Pretoria, for a taxonomic study of the legume genus Elephantorrhiza Bentham (1841: 344) (see for example Grobler & Van Wyk 2010). In 2006, after serving a brief stint as an intern in the South African National Biodiversity Institute’s National Herbarium (Herb. PRE), Pretoria, she was appointed as curator of the legume collection in the same institution. In 2010 she moved to the Institute’s Publications Section as a scientific editor, a post she still holds.

Figures

FIGURE 2. Kalanchoe krigeae. A. From northeastern Mpumalanga, South Africa. B. Plants are often very few-leaved and -flowered. C. Leaves are light green to very light glaucous, with a slight bloom and turgid during the rainy season. D. The usually narrowly elliptic corolla lobes spread at an angle of between 45° and 90° and are sometimes sigmoidally down- and upcurved, The adaxial surfaces of the narrowly elliptic lobes of this form are apricot-orange and rounded-acute. E. The adaxial surface of the corolla lobes of K. krigeae (flower on the left) is uniformly apricot-orange.A flower of similar age of K. rotundifolia (flower on the right) is shown for comparative purposes. F. Alicia Krige (1982–) for whom K. krigeae is named. All photographs by Gideon F. Smith, except F, which was taken by Lawrette McFarlane in June 2022.