Kalanchoe [subg. Calophygia] sect. Trichanthae (A.Berger) Gideon F.Sm, 2023

Smith, Gideon F., 2023, Publication of Kalanchoe sect. Trichanthae (Crassulaceae subfam. Kalanchooideae), a new status for K. [infragen. unranked] Trichanthae of Alwin Berger (1930), in K. subg. Calophygia (2006 as amended in 2023), Phytotaxa 616 (2), pp. 176-182 : 178-180

Kalanchoe [subg. Calophygia] sect. Trichanthae (A.Berger) Gideon F.Sm ., stat. nov.

Basionym:— Kalanchoe [infragen. unranked] Trichanthae Berger (1930: 406, as “§ 4”).

Type:— Kalanchoe trichantha Baker (1883: 140) , which is currently accepted as a synonym of K. synsepala Baker (1882: 110) . The epithet used in the name K. [infragen. unranked] Trichanthae is derived from the epithet of one of the originally included species names, K. trichantha ( Turland et al. 2018: Art. 10.8 and its Ex. 12) (see Smith 2020b: 52).

Homotypic synonym:— Kalanchoe [sect. Kalanchoe ] subsect. Trichanthae ( A.Berger) Boiteau (1947: 9), as “ Trichantae ”.

Included species:—Three. Kalanchoe synsepala Baker (1882: 110) [including K. trichantha Baker (1883: 140) , K. synsepala var. trichantha (Baker) Boiteau & Allorge-Boiteau (1995: 178–179) , and “ K. synsepala var. dissecta ” Rauh (1995: 196), nom inval. ( Turland et al. 2018: Art. 39.1)]; K. tetraphylla Perrier de la Bâthie (1923: 452) ; and K. berevoensis Rebmann (2017: 3) .

Diagnosis:—Taxa included in K. sect. Trichanthae are low-growing, pseudo-rosulate, seldom-branched perennials that remain stemless or in time develop a sturdy stem ( Fig. 1A ). The only known stoloniferous kalanchoe, K. synsepala , is included in the section ( Fig. 1B ). Leaves are generally tough, succulent, and their margins are variously adorned with shallow or deep indentations ( Fig. 1A ). The generally dull-coloured, tubular or campanulate flowers are borne erectly or flexed patent-erect at anthesis, and densely arranged in corymbose cymes that are carried terminally on often gracefully arched peduncles ( Fig. 1C–F ). Flowers are distinctly or obscurely finely hairy. The calyx is substantially fused into a tube. Nectary scales are longer than wide.

Description:—Perennial, acaulescent to short-caulescent, sometimes laterally branched or stoloniferous, glabrous to hairy, small to medium-sized, succulent, solitary or forming dense clusters. Stems generally absent or short if present, rarely to ± 0.4 m long in old specimens, woody-sturdy, erect to leaning, internodes short, leaf scars prominent. Leaves few, decussate, generally tightly arranged to yield pseudo-rosulate appearance, glabrous to variously hairy, tough, spreading to erectly spreading, sessile to petiolate; blade light green, often with scattered brownish spots, generally large, ovate-spathulate to oblong-lanceolate, often longitudinally folded upwards, sometimes episodically shed in dry, brown sections; petiole flattened if present; base truncate to attenuate, ± amplexicaul; apex rounded to blunt-tipped-acute; margins entire to variously dentate, sometimes distinctly reddish brown-infused. Inflorescence an axillary corymbose cyme, usually two produced simultaneously, often oppositely, many- and densely-flowered; peduncle slender, at first erect, then gracefully arched, with closely- or widely-spaced shark tooth-like outgrowths, small, transitional bract-like leaves present, variously finely to distinctly hairy; pedicels usually stout, broadening distally. Flowers erect to pendant, overall variously hairy; calyx small, globular to tubular below, obvious or hardly contrasting against base of corolla tube, finely hairy, pencil-shaped in bud; sepals substantially fused, free sepal segments short, triangular-deltoid, acutetipped, ± pale green, sometimes pinkish purple-infused towards tips of free sepal segments; corolla generally dull-coloured, white to light pinkish with darker pinkish or purplish, longitudinal veins, stout, often 4-angled; corolla tube ± cylindrical to campanulate, drying whitish brown to dark brown, purplish veins retained, shrinking in length when desiccating to expose styles and stigmas; corolla lobes strongly spreading to variously recurved, ovate to obovate, usually apically rounded, abruptly or gradually short-acuminate. Stamens inserted very high up the corolla tube, in ± 2 ranks, shortly exserted; filaments short, ± 1–2 mm long; anthers large, yellowish grey, ovate-elliptic. Pistil consisting of 4 carpels; carpels light to mid-green, oblong-lanceolate; styles whitish green, often purplish red towards stigma; stigmas slightly capitate, drying purplish; nectar scales narrowly linear, to nearly hair-like, transparent-white. Follicles brittle, grass spikelet-like when dry, enveloped in dry, dark velvety brown remains of corolla, light green at first, drying light brown. Seed light brown to reddish brown, rectangular-straight or banana-shaped-curved, slightly apiculate at one end, longitudinally striated. Chromosome number (of K. synsepala ): n = 36, 2 n = 72 (Baldwin 1938: 576, Smith 2022b: 161, 166). Note that K. subg. Calophygia sensu Smith (2023a) includes several polyploids (Smith 2022b).

Figures

FIGURE 1. Kalanchoe synsepala, one of the species included in K. sect. Trichanthae. A. Plants are low-growing, pseudo-rosulate, seldom-branched perennials. Leaves are distinctly succulent and their margins are variously adorned with shallow or deep indentations. Note the scattered brown spots on the leaf surface. B. It is the only known stoloniferous kalanchoe. C. The peduncle is slender and at first held erectly. Note the shark tooth-like, lateral outgrowths. D. The calyx is substantially fused into a globule-like tube. E. Flowers are distinctly or obscurely finely hairy. The adaxial surface of the corolla lobes of this light pinkish-flowered variant is longitudinally distinctly adorned with darker, purplish veins. F. The adaxial corolla surface of this variant is nearly pure white, with only a slight light pink-infusion.All photographs: Gideon F. Smith.