Kalanchoe × vadensis Boom & Zeilinga (1964: 124)

Smith, Gideon F., 2022, The taxonomy and nomenclature of Kalanchoe × vadensis [K. blossfeldiana × K. marmorata var. somaliensis] (Crassulaceae subfam. Kalanchooideae), an early nothospecies produced in The Netherlands in the 1950 s, Phytotaxa 561 (2), pp. 199-209 : 202-205

Kalanchoe × vadensis Boom & Zeilinga (1964: 124) .

Type:— THE NETHERLANDS. Wageningen , Rijks Landbouw Hoogeschool, Institute of Horticultural Plant-breeding, ex hort., 25 February 1961, B. K. Boom 24038, (holotype L barcode L.1860830!) .

Epitype (designated here):— THE NETHERLANDS. Wageningen , Institute for Plant Breeding, in greenhouse, ex hort., 11 March 1982, J . van Veldhuizen 794, (epitype WAG [Herbarium Vadense], barcode WAG 1212259 !; iso-epitype WAG [Herbarium Vadense], barcode WAG 1212260 !) .

Parentage:— K. blossfeldiana Von Poellnitz (1934: 159) ♀ × K. marmorata Baker (1892: 300) ♂, as “ K. grandiflora ”, i.e., K. grandiflora Richard (1847: 310)

Notes on the holo- and epitype of the name Kalanchoe × vadensis :—When Boom & Zeilinga (1964: 124) published the name K. × vadensis , they stated that the “ Type [is] in [the] Rijksherbarium [Herb. L], Leiden”, i.e., without providing further details. A specimen was found at Herb. L with the following information reflected on the specimen label: “Herbarium B.K. Boom 24038, Plantae cultae. Kalanchoe blossfeldiana v.Poelln × K. somaliensis Hook.f. [sic, it should have been “Baker”; and, now, K. marmorata Baker var. somaliensis (Baker) Smith (2022c: 107) ]. Leg.: d.d. 25.2.1961 det. B. Loc.: Wageningen, de Goor, coll. Cr. 2391 kruising hier [Wageningen, The Netherlands] gemaakt: bloemen lilarood. [English: “cross made here [Wageningen, The Netherlands]: flowers lilac red”]; (barcode L.1860830). A small label stating: “HERB. LUGD. BAT. No 961293 577” is affixed to the top right corner of the specimen. The number 901150 has been stamped in the centre bottom of the specimen.

This B.K. Boom specimen was prepared more than three years before the description of K. × vadensis was published and Boom is one of the authors of the name. The material coincides with the description in virtually all respects, as well as with the rest of the protologue, although Boom, in the case of the text on the specimen label replaced “ K. grandiflora ” with “ K. somaliensis Hook.f. ”, which, as shown above, refers to K. marmorata , now K. marmorata var. somaliensis , so corroborating the interpretation of Kroon (1994: 125) regarding the parentage of K. × vadensis , apart from K. blossfeldiana . Under Turland et al. (2018: Art 9.1) the specimen B.K. Boom 24038 is interpreted as the holotype of the name K. × vadensis .

The holotype consists of an inflorescence only ( Fig. 3 ). A more complete specimen that includes vegetative and reproductive material is here designated as epitype ( Fig. 4 ). Additionally, this specimen was prepared from material cultivated at the Institute for Plant Breeding where the nothospecies was originally created in 1954 ( Boom & Zeilinga 1964: 122).

Amplified description:—Perennial, usually sparsely leaved, unbranched or sparsely branched, glabrous throughout, small to medium-sized, succulent shrublets, 0.5–1.0 m tall. Stems green to reddish brown-infused, somewhat fleshy, a few arising from low down or higher up after flowering, erect to leaning, round in cross-section. Leaves opposite-decussate, petiolate, mid- to dark green, reddish-infused especially along margins if grown in exposed positions, shiny, succulent, spreading to spreading-erect, papery on drying; petiole 20–30 mm long, slightly to distinctly channelled above, leaves not or hardly amplexicaul; blade (60–)100(–120) × (60–)100(–120) mm, round to somewhat obovate, flat or oyster shell-like cupped upwards, slightly to distinctly channelled along midrib, venation indistinct; base cuneate to ± straight; apex rounded-obtuse; margins coarsely crenate or undulate-crenate into rounded, harmless teeth virtually along entire length, sometimes reddish-infused. Inflorescence 150–300(–500) mm tall, erect to leaning, apically dense, many-flowered, ± flat-topped thyrse, branches opposite, erect, subtended by leaf-like bracts, lacking leafy branchlets in axils, axis light to dark green; pedicels 10 mm long, slender. Flowers erect, 4-merous; calyx shiny light green, infused with small red spots especially towards tips and margins; sepals 7(–10) mm long, fused for ± 0.25–0.50 mm, separate above, triangular-lanceolate, acute-tipped, clasping corolla tube above, hardly contrasting against lower portion of corolla tube; corolla 22–26 mm long, slightly enlarged lower down, not twisted apically after anthesis, tube 20–25 mm long, slightly 4-angled, light greenish yellow lower down, pinkish purple-infused high up, especially along angles, large-rounded to slightly box-shaped-square when viewed from below, tapering upwards, slightly longitudinally fluted above; lobes 8–10 × 6–8(–10) mm, uniformly bright pinkish red above, white to strongly minutely pink-spotted below, ovate, rounded-acute at apex, mucronate. Stamens 8, inserted in two ranks, one at midtube, the other well above middle of tube, all eight slightly exserted, four more so; filaments thin, yellow; anthers 0.3–0.5 mm long, visible at mouth, rounded to slightly elongated. Pistil consisting of 4 carpels; carpels 10(–12) mm long, bright shiny light green; styles 10(–12) mm long, red; stigmas capitate, whitish yellow, visible at mouth of corolla tube; scales size, shape, and colour not recorded. Follicles not seen. Seeds not seen. Chromosome number: 2 n = 136, i.e., an artificially-produced, (self-)fertile, amphitetraploid ( Kroon 1994: 125); see the text for a discussion of the chromosome numbers of the two parents.

Flowering time: August–November, peaking in September (southern hemisphere).

Derivation of name:—The specific epithet, ‘ vadensis ’ means “originating from Vada (Wageningen)” ( Boom & Zeilinga 1964: footnote on p. 122); Herb. WAG is also referred to as “Herbarium vadense”. Kalanchoe × vadensis was named for Wageningen, The Netherlands, by Boudewijn Karel Boom (1903–1980), a Dutch botanist, and A.E. Zeilinga (fl. 1964), presumably also a Dutch botanist. Little has been recorded about these two authors and as far as could be determined, K. × vadensis is the only species they described.

Figures

FIGURE 3. The holotype of the name Kalanchoe ×vadensis. The metadata associatedwith the specimen are:The Netherlands.Wageningen, Rijks Landbouw Hoogeschool, Institute of Horticultural Plant-breeding, ex hort., 25 February 1961, B.K. Boom 24038, (holotype L barcode L.1860830). Institution: Naturalis Biodiversity Center; Source: Naturalis—Botany catalogues. License: CC0 1.0. Reproduced with permission. https://data.biodiversitydata.nl/naturalis/specimen/L.1860830

FIGURE 4. The epitype, designated in this paper, which supports the holotype of the name Kalanchoe ×vadensis. The metadata associated with the specimen are:The Netherlands.Wageningen,Institute for Plant Breeding.In greenhouse,ex hort.,11 March1982, J.vanVeldhuizen 794, (epitype WAG [Herbarium Vadense], barcode WAG 1212259). Reproduced with permission. For attribution of the photograph see Bijmoer et al. (2021).