Kalanchoe × oberlanderi Gideon F.Sm., 2023

Smith, Gideon F., 2023, Kalanchoe × oberlanderi (Crassulaceae subfam. Kalanchooideae), a horticulturally successful nothospecies with the Malagasy K. blossfeldiana and K. manginii as parents, Phytotaxa 594 (1), pp. 64-72 : 67-69

Kalanchoe × oberlanderi Gideon F.Sm. nothospec. nov.

( Fig. 2A–F ).

Type:— SOUTH AFRICA. Gauteng province —2528 (Pretoria): Tshwane , (– CA), ex hort., 03 September 2022, G. F. Smith 1199 ( PRU holotype) .

Parentage:— Kalanchoe blossfeldiana Von Poellnitz (1934: 159) × K. manginii Hamet & Perrier de la Bâthie (1912: 370) .

Diagnosis:— Kalanchoe × oberlanderi is a few- to many-leaved and -branched, very finely pubescent or more rarely glabrous, tuft-forming succulent that in both vegetative and reproductive morphological characters is intermediate between its parents, K. blossfeldiana and K. manginii . The stems and branches of K. × oberlanderi are thin and somewhat brittle woody, like those of K. manginii , while K. blossfeldiana is a small, herbaceous-shrubby species. The generally obovate to orbicular to cordate leaves of K. × oberlanderi are smaller than the ovate-oblong to oblong ones of K. blossfeldiana , but usually larger than the obovate to spathulate ones of K. manginii . The bright crimson red to lighter red to pinkish corolla tube of K. × oberlanderi is slightly enlarged above the middle, i.e., widening towards the mouth, with that of K. blossfeldiana being light green and red-infused and gradually urceolate, and that of K. manginii being orange-red to deep crimson red and campanulate.

Description:—Perennial, few- to many-leaved, few- to multi-branched from base, very finely pubescent or more rarely glabrous, tuft-forming succulent, to 600 mm tall. Stems few, brittle-woody, brown to reddish brown, older internodes with longitudinal light brownish or greenish lines, unbranched or sparsely branched, erect to leaning, sometimes creeping, rooting along the way, leaning branches sometimes developing short, near-woody stilt-like roots, nodes thickened, round; sterile and reproductive stems finely pubescent to, rarely, glabrous. Leaves oppositedecussate, subsessile to distinctly petiolate, light to mid-green to variously infused with red, succulent, lower older ones spreading to horizontal to decurved, upper younger ones ± vertical, papery on drying; petiole to 10 mm long if present, channelled above, not clasping the stem; blade 10–30 × 10–20 mm, obovate to orbicular to cordate or somewhat oblong, flat, sometimes curved upwards towards margin; apex rounded-obtuse; base ± cuneate; margins weakly crenate to entIre especIally In upper ⅔, pubescent. Inflorescence a terminal, branched, erect, apically sparse to dense, few- to many-flowered, flat-topped cyme with several dichasia, 180–200 mm tall, rounded when viewed from above, branches opposite, erectly spreading, subtended by very small leaf-like bracts, lacking leafy branchlets in axils, without bulbils; peduncle generally bright red, minutely white-hairy; pedicels slender, 8–10 mm long. Flowers tetramerous, 19–21 mm long, erect to erectly spreading to pendent; calyx light to dark reddish green, strongly infused with small red spots especially towards sepal margins; sepals 4, ± separate, basally fused for ± 1 mm, 4–6 × 3–4 mm, triangular-lanceolate, acute-tipped, hardly contrasting against light green basal part of corolla tube, minutely white-hairy, not adnate to lower part of corolla tube; corolla 18–20 mm long, slightly enlarged above the middle, not twisted apically after anthesis, minutely white-hairy, drying purple-red; corolla tube 16–18 mm long, ± to distinctly 4- angled-cylindrical, box-shaped-square when viewed from below, bright crimson red, sometimes lighter red to pinkish, light green lower down ± at level of calyx, minutely white-hairy; lobes 4.5–5.0 × 4.5–5.0 mm, bright crimson red, sometimes lighter pinkish red, ovate to suborbicular, rounded at apex, apiculate. Stamens 8, inserted at about the middle of the corolla tube, ± included; filaments 6–7 mm long, thin, yellow, ± adnate to corolla tube; anthers 0.5 mm long, arrowhead-shaped, purplish brown when pollen shed. Pistil consisting of 4 carpels; carpels 6–7 mm long, light green, sometimes slightly red-infused; styles 8–9 mm long; stigmas capitate, whitish yellow; nectar scales 1.5–2.0 mm long, ribbon-like-linear, slightly tapering upwards, light yellowish green. Follicles 6–7 mm long, dull whitish green, brittle, grass spikelet-like, enveloped in dry, purplish remains of corolla. Seed 0.50–0.75 mm long, light brown. Chromosome number: unknown. [Chromosome numbers of parents: K. manginii 2 n = 34 and K. blossfeldiana 2 n = 34, see Smith 2022d: 158 and 161, respectively].

Flowering period:—Like most kalanchoes, K. × oberlanderi is a short-day plant that flowers mainly in the winter months, but as is the case with K. blossfeldiana , one of its parents, material can be manipulated to bloom at other times of the year (see Smith et al. 2019: 97–98 for a discussion).

Eponymy:— Kalanchoe × oberlanderi is named for Dr Kenneth Carl Oberlander ([George, Western Cape, South Africa] 16 September 1978 –) ( Fig. 3 ). Kenneth completed his Ph.D. at the University of Stellenbosch, South Africa, after which he completed post-doctoral appointments at that University, and in Prague, Czech Republic. He is at present a senior lecturer in the Department of Plant Sciences, University of Pretoria, South Africa, and Head of the University’s H.G.W.J. Schweickerdt Herbarium [Herb. PRU]. Dr Oberlander’s research interests are principally in plant systematics, with specific emphasis on polyploidy and its evolutionary effects, and in phylogenetics and biogeography. He is an authority on Oxalis Linnaeus (1753: 433) and recently participated in a survey of the conservation status of Kalanchoe in southern Africa.

Figures

FIGURE 2. Kalanchoe ×oberlanderi. A. The shape of the leaves of K. ×oberlanderi is intermediate between that of K. blossfeldiana and K. manginii, with the leaves of K. ×oberlanderi generally being larger than those of K. manginii, but smaller than those of K. blossfeldiana. Leaf margins of K. ×oberlanderi are often weakly crenate especIally In the upper ⅔. B. The weakly campanulate and very finely pubescent flowers are variously borne erectly to pendent, but are usually spreading. C. The corolla tube varies from bright crimson red to lighter red to pinkish (see ‘D.’ for the size of the flowers). D & E. Comparison of the flowers of K. blossfeldiana (throughout the flower on the left), K. ×oberlanderi (throughout the flower in the centre), and K. manginii (throughout the flower on the right). D. Lateral view (see Table 1 and ‘Results’ for a discussion), with the flowers of all three taxa here arranged vertically. E. Colour and ornamentation of the adaxial corolla lobe surface (see Table 1 and ‘Results’ for a discussion). F. When K. ×oberlanderi is in full flower during the winter months, the floral display is spectacular. All photographs: Gideon F. Smith.

FIGURE 3. Dr Kenneth C. Oberlander (1978–), after whom K. ×oberlanderi is named. Kalanchoe sexangularis Brown (1913: 120) grows densely in the raised garden bed in the background. Photograph taken on 27 October 2022 by Gideon F. Smith.