Kalanchoe, Adanson, 1763

Smith, Gideon F., 2021, Kalanchoe × leistneri (K. sexangularis × K. winteri) (Crassulaceae subfam. Kalanchooideae), a new southern African nothospecies, Phytotaxa 509 (2), pp. 248-254 : 250-251

Kalanchoe × leistneri Gideon F.Sm. nothospec. nov. ( Fig. 2A–E ).

Type:— SOUTH AFRICA. Gauteng province —2528 (Pretoria): Pretoria , (– CA), ex hort., 28 March 2021, G . F . Smith 1146 (holotype PRU) .

Parentage:— Kalanchoe sexangularis Brown (1913: 120) var. sexangularis × Kalanchoe winteri Gideon F.Sm., N.R.Crouch & Mich. Walters in Crouch et al. (2016a: 219).

Diagnosis:—Plants of Kalanchoe ×leistneri are medium-sized to large, glabrous, non-waxy, bi- to triennial to perennial succulents that are intermediate between its parents, K. sexangularis var. sexangularis and K. winteri . The distinctly red-infused leaf colour of K. × leistneri ( Fig. 2A ) was inherited from K. sexangularis var. sexangularis , as was its distinctly decussate leaf arrangement. Kalanchoe ×leistneri differs from K. winteri by its leaves usually being light green with a strong infusion of red; by the leaves being more obovate (paddle-shaped) rather than round (as in K. winteri ); with the leaf margins being shallowly scalloped (as in K. sexangularis var. sexangularis ) ( Fig. 2B ) rather than perfectly smooth (as in K. winteri ). The leaf bases of K. × leistneri are cuneate to narrowly triangular as in K. sexangularis var. sexangularis , but often distinctly auriculate ( Fig. 2C ) as in K. winteri . The inflorescences of K. × leistneri are more densely flowered than in K. sexangularis var. sexangularis , but less dense than in K. winteri ( Fig. 2D ). The corolla tubes of K. × leistneri are tubular-urn-shaped and light yellowish green, and therefore intermediate between those of K. sexangularis var. sexangularis and K. winteri , but the tubes lack a waxy covering, unlike those of K. winteri that are densely waxcovered. The corolla lobes are bright yellow as in both the parents of K. × leistneri ( Fig. 2E ).

Description:—Bi- to triennial to perennial, few-leaved, unbranched at first, pre- and/or post-flowering slowly sprouting from base, glabrous, medium-sized to robust succulent, 0.9–1.8 m tall when in flower. Stems reddish light green to deep wine-red, unbranched or with few branches, arising from sturdy base, erect to leaning, often with few distinct, lengthwise running ridges, somewhat 4-angled on sterile and fertile shoots. Leaves opposite-decussate, not petiolate, light green infused with red to orangey red, reddish infusion more intense towards leaf margins, succulent, spreading to erectly spreading, not longitudinally recurved, coriaceous and papery-flimsy on drying; petiole absent, leaves clasping stem; blade 120–200 × 65– 80 mm, obovate to broadly elliptic, somewhat folded upwards lengthwise, sometimes very slightly wavy, flat to slightly curved up along margins; base cuneate to narrowly triangular, often distinctly auriculate; apex rounded-obtuse; margins coarsely crenate or undulate-crenate into rounded, harmless, crenations, more rarely smooth, slightly saucer-like curved upwards. Inflorescence erect to slightly leaning, apically sub-dense to dense, many-flowered, diffusely club-shaped to loosely branched thyrse consisting of several dichasia terminating in monochasia, flowering portion 500–700 mm long, branches opposite, sometimes only one at node, erect to slanted away from main flowering stem at angle of 30°, subtended by leaf-like bracts, sometimes with leafy branchlets in axils, axis reddish green to bright crimson red, central axis longest; pedicels 3–8 mm long, slender. Flowers erect to erectly spreading at anthesis; calyx light shiny green; sepals ± 3.0–3.5 × 1.0– 1.5 mm, narrowly triangular-lanceolate, succulent, fully separate above, basally fused for ± 1 mm, acute-tipped, hardly contrasting against light yellowish green corolla tube; corolla 14–15 mm long, enlarged lower down, tapering to mouth, not twisted apically after anthesis; tube 13–14 mm long, light yellowish green, tubular-urn-shaped, indistinctly 4-angled, round when viewed from below, longitudinally indistinctly fluted above; lobes 5 × 4 mm, bright yellow, ovate-rectangular, straight lower down, tapering towards apex, margins slightly to distinctly in-folded, horizontally spreading or strongly recurved, browntipped in bud, apiculate. Stamens 8, inserted in two ranks, one rank just above middle of corolla tube, other further above middle of corolla tube, 4 slightly exserted, 4 included but visible at mouth; filaments 4–5 mm long, yellow, thin, tapering upwards; anthers 0.75–1.00 mm long, yellow. Pistil consisting of 4 carpels; carpels 8–9 mm long, shiny light green; styles 3.5–4.0 mm long, light green; stigmas very slightly capitate, whitish yellow; scales ± 2 mm long, ± 1 mm broad at widest point at base, tapering towards apex, flat to slightly tooth-like rounded apically, uniformly light yellow. Chromosome number: unknown.

Flowering time:— Kalanchoe ×leistneri flowers mainly in the autumn and winter months, (March–)April to August in the southern hemisphere. Its flowering period more closely approximates that of K. sexangularis var. sexangularis , which generally flowers as early as late-autumn (April) and as late as early-summer (November). Kalanchoe winteri generally has a shorter flowering period that stretches from winter (May/June) to spring (September), peaking in July.

Eponymy:— Kalanchoe × leistneri is named for Dr Otto Albrecht Leistner (21 April 1931 [Leipzig, Germany]–) ( Fig. 2F ) who, at the age of 16, moved to South Africa with his parents. Two years later he enrolled at Stellenbosch University, eventually graduating with an M.Sc. in plant systematics (1954) and a D.Sc. in plant ecology (1964). In 1955 Otto joined the staff of the Botanical Research Institute (BRI), one of the forerunners of the present-day South African National Biodiversity Institute (SANBI). Two years after his appointment to the BRI, he was stationed in Kimberley (1957–1963) before being appointed as the South African Botanical Liaison Officer at the Royal Botanic Gardens, Kew (1965–1967). On his return to South Africa he was based in Pretoria where he was Head of the Herbarium Services Section (1965–1976) and from 1976 Head of the BRI’s Flora Research Section ( Gunn & Codd 1981: 221). In 1986 Otto took over the editorship of Bothalia and after the BRI and the National Botanic Gardens of South Africa amalgamated to form the National Botanical Institute he was appointed as Head of the new Institute’s Publications Section. In 1997 Otto retired from SANBI, but was contractually retained to produce several benchmark publications, such as Leistner (2000), which was launched on 23 August 2000, and Leistner (2005) that was launched on 22 February 2005.

Otto’s joint collection, with Bernard de Winter (Bernard de Winter & Otto A. Leistner 5579, Herb. PRE PRE0523579- 0), of K. laciniata Linnaeus (1753: 430) Candolle (1802 : t. 100), made on Otto’s 26 th birthday, which in 1957 coincided with Easter Sunday, remains the only record of that species for the Flora of Southern Africa (FSA) region. The species was collected in central Kaokoland, northwestern Namibia, on a weathered dolomite koppie ( Tölken 1985: 66, Smith et al. 2019b: 167). Otto also edited the FSA treatment of the Crassulaceae , including Kalanchoe ( Leistner 1985) .

The naming of K. × leistneri for Dr Leistner celebrates his 90 th birthday on 21 April 2021.

Figures

FIGURE 2. A. Leaves of Kalanchoe ×leistneri are orange- to red-infused. B. Leaf margins are crenate, as in K. sexangularis, rather than smooth as in K. winteri. C. The leaf bases of K. ×leistneri are sometimes auriculate, as in K. winter. D. Inflorescences of K. ×leistneri are tall-growing. E. The corolla lobes are bright yellow as in both K. sexangularis and K. winteri. F. Dr Otto Leistner, for whom Kalanchoe ×leistneri is named, celebrated his 90th birthday on 21 April 2021.All photographs: Gideon F. Smith, except F: taken by Christina Preisser on 22 February 2021.