Kalanchoe × verdoorniae Gideon F.Sm., 2022

Smith, Gideon F., 2022, Kalanchoe × verdoorniae [K. luciae × K. winteri] (Crassulaceae subfam. Kalanchooideae), a new, large-growing nothospecies from South Africa, Phytotaxa 568 (1), pp. 72-82 : 76-78

Kalanchoe × verdoorniae Gideon F.Sm. nothospec. nov. ( Fig. 2A–D ).

Type:— SOUTH AFRICA. Gauteng province —2528 (Pretoria): Tshwane , (– CA), ex hort., 04 May 2022, G. F. Smith 1182 (holotype PRU) .

Parentage:— K. luciae Hamet (1908: 256) × K. winteri Gideon F.Sm., N.R.Crouch & Mich.Walters in Crouch et al. (2016: 219).

Diagnosis:—Plants of Kalanchoe ×verdoorniae are large to robust, completely white-waxy, bi- to triennial to perennial leaf succulents that are intermediate between its parents, K. lucia and K. winteri . As the waxy layer becomes thinner on older leaves, a light green leaf colour is revealed, as is found in its parents, K. luciae and K. winteri . The pseudo-rosulate, distinctly decussate leaf arrangement of K. × verdoorniae was also inherited from both parents. Kalanchoe ×verdoorniae differs from K. luciae by its leaves generally being slightly smaller and basally conspicuously auriculate, as in K. winteri . Kalanchoe ×verdoorniae further differs from its other parent, K. winteri , by its leaves being consistently obovate(paddle-shaped) rather than sometimes round. The inflorescences of K. × verdoorniae are denseflowered,as found in both parents. The corolla tubes of K. × verdoorniae , as well as those of K. luciae and K. winteri are cigar-shaped and densely white-waxy-covered. However, with the white-flowered form of K. luciae having been used as one parent when producing K. × verdoorniae , the adaxial surface of the corolla lobes of the nothospecies is light yellow, with that of K. winteri being more intensely yellow.

Description:—Bi- to triennial to perennial, few- to many-leaved, unbranched, post-flowering slowly sprouting from base, completely white-waxy, large, robust succulent, 1.75–2.50 m tall when in flower. Stems light greenish white, unbranched or with few branches arising from sturdy base, erect to leaning, sterile and fertile shoots round in crosssection. Leaves opposite-decussate, light green, densely white-wax-covered at first, succulent, spreading to erectly spreading, not longitudinally recurved, coriaceous and papery-flimsy when dry; petiole absent, leaves clasping stem; blade 200–250 × 120–140 mm, lacking red infusion, obovate, flat; base cuneate, distinctly auriculate; apex roundedobtuse; margins sometimes with very faint red infusion, smooth, flat. Inflorescence an erect to leaning, dense-, manyflowered, club-shaped thyrse consisting of several dichasia terminating in monochasia, flowering portion 350–500 mm long, branches opposite, very short, subtended by leaf-like bracts, sometimes with leafy branchlets in axils, axis light greenish white, white-waxy-covered; pedicels 6–8 mm long, slender. Flowers horizontally-spreading at anthesis; calyx consisting of 4 sepals, light green, densely white-wax-covered; sepals 4.0–5.0 × 2.0– 2.5 mm, triangular-lanceolate, succulent, basally fused for ± 1 mm, acute-tipped, hardly contrasting against light green corolla tube; corolla 11–14 mm long, tapering to base and mouth, not twisted apically after anthesis; tube 10–13 mm long, light greenish yellow, white-wax-covered, cigar-shaped, indistinctly to distinctly 4-angled, round when viewed from below, longitudinally indistinctly fluted in bud; lobes 5–7 × 3.0– 3.5 mm, uniformly pale yellow, elongated-triangular, ± straight lower down, tapering towards apex, margins often distinctly in-folded, horizontally spreading at first, later strongly recurved, yellowtipped in bud, blunt-tipped. Stamens 8, inserted in two indistinct ranks, both ranks high up in corolla tube; filaments 3.5–5.0 mm long, whitish yellow, thin, tapering upwards; anthers 0.75–1.00 mm long, reddish orange in bud before anthesis, yellow at anthesis, all 8 distinctly exserted. Pistil consisting of 4 carpels, stipitate; carpels 5–6 mm long, light green; styles 3.5–4.0 mm long, light green; stigmas minutely capitate, yellowish green; scales 2.0–2.5 × 2.00– 2.25 mm, ± square, slightly tapering towards base, minutely but distinctly repand apically, light yellow in distal ⅔, light green in proximal ⅓. Fruit not recorded. Seed not recorded. Chromosome number: unknown.

Flowering time:— Kalanchoe ×verdoorniae flowers mainly in the autumn and winter months, (March–)April to July in the southern hemisphere.

Eponymy:— Kalanchoe × verdoorniae is named for Dr h.c. Inez Clare Verdoorn (born 15 June 1896, Pretoria, Gauteng, South Africa –died 02 April 1989, Pretoria, Gauteng, South Africa) ( Gunn & Codd 1981: 361, Fourie 1989) ( Fig. 3 ). In 1919, at the age of 23, she was appointed to Herb. PRE, the National Herbarium of South Africa, and carried on working at the Herbarium until 1980, i.e., for 29 years after she retired in 1951. In 1979 she published her final plant name, so crowning a species-description career of 60 years. She started at Herb. PRE as an herbarium assistant mounting specimens but, even without formal botanical qualifications, rose to the professional officer ranks in the civil service and in 1944, until her retirement, served as Curator of the National Herbarium. She published several hundred papers, including a pioneering Afrikaans botanical text book ( Verdoorn 1942). Inez was widely respected and the undisputed doyenne of South African botany during the 20 th century; in 1967 an honorary doctorate was conferred on her by the University of Natal, now the University of KwaZulu-Natal ( Germishuizen 1976: 45, Figueiredo & Smith 2021: 282, 287–288, 292, 306). In 1946 she described Kalanchoe crundallii Verdoorn (1946 : t. 967) from the Soutpansberg, Limpopo province, South Africa ( Hahn 2002, 2017, Smith & Hahn 2019).

Figures

FIGURE 2. Kalanchoe ×verdoorniae. A. Basally, the leaves of K. ×verdoorniae are pronouncedly auriculate, as in K. winteri. B. All plant parts of K. ×verdoorniae, including the very tall-growing inflorescence and the external surface of the flowers, are strongly white-waxcovered. C. Leaves of K. ×verdoorniae are obovate and in size intermediate between those of K. luciae and K. winteri. D. Colour-wise, the adaxial surface of the corolla lobes is light yellow and intermediate between those of K. luciae and K. winteri. All photographs: Gideon F. Smith.

FIGURE 3. Dr h.c. Inez Clare Verdoorn (1896–1989), for whom K. ×verdoorniae is named. Photograph © and reproduced with the permission of the South African National Biodiversity Institute.