Kalanchoe Adanson (1763: 248)

Smith, Gideon F., 2024, An alternative subgeneric classification of Kalanchoe (Crassulaceae subfam. Cotyledonoideae) globally: a nomenclatural and taxonomic review, with a new status for K. subg. Pubescentes, Phytotaxa 665 (3), pp. 201-220 : 206-214

Kalanchoe Adanson (1763: 248) .

Type:— Cotyledon laciniata Linnaeus (1753: 430) , currently accepted name Kalanchoe laciniata ( L.) Candolle (1802: t. 100), designated by Tölken (1985: 61).

Heterotypic synonyms [in chronological sequence]:— Vereia Andrews (1798: t. 21); Bryophyllum Salisbury (1805 : t. 3); Physocalycium Vest (1820: 409) ; Baumgartenia Trattinnick (1821: 110 , 315, t. 59), nom. illeg.; Meristostylus Klotzsch (1861: 267) ; Kitchingia Baker (1881: 268) ; Geaya Costantin & Poisson (1908: 636) [the types of these names are given in Smith (2024c)]; × Bryokalanchoe Resende (1956: 241) [type not applicable because this is a condensed formula ( Turland et al. 2018: Note 1 under Art. H.9.1)].

Designation not validly published:—“ Crassuvia ” / “ Crassouvia ” Commerson, manuscript or in sched. name, nom. inval.

Notes:— Smith (2024c) provides additional information on the genus-rank synonymy of Kalanchoe , as well as on the sub genus-rank synonymy of the genus names included in the synonymy of Kalanchoe . All the various orthographical variants and typographical errors of the names Kalanchoe and Vereia are discussed in Smith (2024c: 239–243, 2024f: 22–24).

Description:—Perennial, variously multiannual, sometimes apparently monocarpic but often perennial through basal sprouts, biennial, more rarely with individual plants annual, smooth, waxy, or tomentose, succulent shrublets, subshrubs, or shrubs, rarely treelike, often sprouting basally or higher up, terrestrial or more rarely epiphytic or lithophytic. Roots flimsy, fibrous, rarely thickened, tuberous, or woody. Stems branched or unbranched, erect to spreading to leaning, succulent, often weak, herbaceous, brittle, sometimes woody throughout or only basally ± woody. Leaves opposite, decussate, sometimes alternate or whorled, rarely subrosulate, free or basally slightly fused to amplexicaul, succulent, smooth, waxy, or tomentose, persistent or deciduous, petiolate or sessile; blade usually flat, simple or 3- to 5- to many-foliolate, sometimes terete, often varying morphologically on one individual; margins entire or crenate, serrate, or dentate with small to large, harmless teeth, sometimes bulbiliferous. Inflorescences terminal, rarely axillary, one- to few- to many-flowered, corymbose, cymose, or paniculate, sometimes thyrsoid consisting of several dichasia, usually terminating in monochasia, sometimes bulbiliferous especially post-flowering, stem growing tip often gradually transitioning into peduncle with regular basal leaves, bract-like leaves higher up similar but much smaller. Flowers tetramerous, very rarely 5- to 8-merous, erect, spreading, or pendulous, usually brightly coloured, pedicellate; pedicels flimsy or sturdy, of constant diameter throughout or variously broadening towards calyx or inflorescence branch; calyx 4-partite, with sepals free or variously fused, sometimes very prominent and obscuring much of corolla tube; calyx tube inconspicuous or prominent, sometimes inflated with short lobes; corolla 4-partite, fused into short or long tube; corolla tube usually much longer than calyx and corolla lobes; corolla lobes erect to variously recurved or fully reflexed; stamens 8, in one or ± two inconspicuous or distinct whorls; filaments glabrous, inserted on corolla tube close to mouth, medially, or in lower ⅓; anthers included or exserted, sometimes with terminal ± spherical connective appendage (gland); carpels 4, free, somewhat connate especially lower down, apically abruptly constricted or gradually lengthening into style; styles filiform, shorter than or much longer than carpels; nectar scales 4, variously shaped, free. Seeds ellipsoid, abundant, very small, variously ridged, grooved, striated, rarely winged. Chromosome numbers: basic chromosome numbers (x) recorded as either 17, 18, or 20; haploid numbers (n) recorded as 17, 18, 20, and 51; diploid numbers (2 n) as 34 (diploid, where n = 17), 36 (diploid, where n = 18), 40 (diploid, where n = 20), 51 (triploid, where n = 17), 68 (tetraploid, where n = 17), 72 (tetraploid, where n = 18), 102 (hexaploid, where n = 17), and 140 (octoploid, where 2 n = ca. 140) (reviewed in Smith 2022a). Chromosome counts doubtfully reported are here excluded (see Table 1 in Smith 2022a: 158–162).

B. Subgenus classification of Kalanchoe

At present five subgenera are recognised in Kalanchoe [‘ C.1’ to ‘ C.5’, below].

Kalanchoe subg. Fernandesiae Smith (2020c: 5) is here treated as a synonym of K. sect. Raveta Smith (2022c: 210) (see also Raymond-Hamet 1916: 83–84, and Smith 2022d: 18–20, 2022e: 131), a distinctive group recognised in K. subg. Kalanchoe .

The five subgenera here upheld in Kalanchoe are, in the chronological sequence in which they were published, along with their basionyms, if applicable, synonyms, and descriptions:

B.1 Kalanchoe subg. Kalanchoe , automatically established in 1919 when K. subg. Bryophyllum was published (see next) ( Turland et al. 2018: Articles 6.8, 22.1, and 22.3) ( Fig. 5 ).

Type:—As for the genus.

Description:—Perennial, short-lived multiannual, or biennial, terrestrial or epiphytic, large or small succulent shrubs or shrublets. Roots fibrous or more rarely substantially thickened, plants sprouting from roots very uncommon. Stems ± herbaceous, often weak, sometimes robust. Leaves variously shaped, not bulbiliferous. Inflorescence not bulbiliferous post-flowering, i.e., they are not flori-bulbiliferous. Flowers usually erect or spreading-erect at anthesis, brightly or dull-coloured; calyx tube usually very short, inconspicuous, often tightly clasping the corolla tube lower down or more rarely diverging from corolla tube; corolla generally flimsy, rarely somewhat succulent; corolla tube not obscured by the minimal calyx tube; corolla tube usually gradually narrowing towards mouth, sometimes constricted ± above the carpels, often yielding narrowly tapering, urn-shaped appearance; stamens ± inserted in upper ½ of corolla tube, often in ± two ranks; filaments often short, of two similar or slightly dissimilar lengths, often near mouth; anthers inserted, then distinctly visible at the mouth, or ± exserted; carpels often as long as styles; nectar scales variously shaped, generally ranging from thin, ribbon-like-linear to large, cuneiform-quadrangular, then apically somewhat 3- lobed. Chromosome number (basic): x = 17.

Kalanchoe subg. Kalanchoe has a very wide natural geographical distribution range that covers the whole of the area of occurrence of the genus (see ‘Introduction’, above). Several species are globally popular in landscaping, gardening, and floriculture (Smith & Shtein 2021a, Smith 2024b).

Morphologically, representatives of K. subg. Kalanchoe are very variable, but they are never arborescent.

B.2 Kalanchoe subg. Bryophyllum (Salisb.) Koorders (1919: 170) ( Fig. 3 ).

Basionym :— Bryophyllum Salisbury (1805 : t. 3).

Type:— Bryophyllum calycinum Salisbury (1805 : t. 3), currently accepted name Kalanchoe pinnata (Lamarck 1786: 141) Persoon (1805: 446) . See Smith & Figueiredo (2018a: 220–222) and Smith (2022f: 88–89).

Homotypic synonym:— Kalanchoe sect. Bryophyllum (Salisb.) Boiteau (1947: 7) , pro parte, excluding K. porphyrocalyx (Baker 1883: 142) Baillon (1885: 469) (see Smith & Shtein 2021b:234–235), when K. subg. Bryophyllum is regarded as undifferentiated.

Description:—Perennial, short-lived multiannual, or biennial, terrestrial, generally medium-sized succulents, sometimes climbing to scrambling. Roots generally fibrous, plants sometimes sprouting from roots. Stems ± herbaceous to brittle-woody, sometimes covered in peeling bark. Leaves variously shaped, almost invariably bulbiliferous, typically at the indentations between crenations or teeth on blade margins, or on adaxial blade surface. Inflorescence often substantially flori-bulbiliferous post-flowering. Flowers usually distinctly pendulous at anthesis, brightly coloured; calyx tube usually conspicuous, often inflated, formed by substantially fused sepals; corolla generally flimsy, damaging easily; corolla tube often substantially obscured by calyx tube, especially lower down at level of carpels; corolla tube indented-constricted ± above carpels, often yielding bulbous appearance; stamens ± inserted in lower ⅓ of corolla tube; filaments of two similar lengths, often adnate to corolla tube very low down; anthers ± exserted or at least distinctly visible at mouth; carpels shorter than styles; nectar scales generally wider than long. Chromosome number (basic): x = 17.

Kalanchoe subg. Bryophyllum is naturally endemic to Madagascar. However, given that several representatives of K. subg. Bryophyllum have multiple reproductive mechanisms, they have a tendency to become naturalised and weedy in places well away from their natural distribution ranges in Madagascar ( Silva et al. 2015, Smith et al. 2021a, Smith 2023a).

Formation of bulbils on the leaves of K. streptantha Baker (1887: 472) has yet to be observed (Smith & Figueiredo 2021b: 199, Smith et al. 2021a: 8, Smith 2023d: 278).

Aspects of the taxonomy of the subgenus were reviewed in Shtein & Smith (2021: 208–211) and in Smith (2022f).

B.3 Kalanchoe subg. Calophygia Descoings (2006: 24) emend. Smith (2023e: 118) ( Fig. 6 ).

Type:— Kalanchoe arborescens Humbert (1933: 163) , designated by Descoings (2006: 24).

Designation not validly published:—“ Kalanchoe [infragen. unranked, as “§”] Lanigerae ” Boiteau (1947: 9), nom. inval. ( Turland et al. 2018: Art 39.1). See Boiteau & Allorge-Boiteau (1995: 16 [page unnumbered], 138–172, as Groupe X) and Allorge-Boiteau (1995, 1996: 141).

Description:—Perennial, woody, generally multi-branched, low-growing, pseudo-rosulate to shrubby or arborescent, terrestrial succulents, stoloniferous in one instance; virtually all external surfaces variously covered by tomentum consisting of glandular or stellate hairs or minute scales. Roots fibrous or substantially thickened, then woody, plants often sprouting from roots. Stems brittle- to very hard-woody. Leaves generally not bulbiliferous, but new plants develop from severed leaves or leaf fragments under ambient growing conditions. Inflorescences terminal or, rarely, lateral, bulbils sometimes develop on inflorescences post-anthesis. Flowers multi-directional to rarely erect at anthesis, brightly or dull-coloured; calyx tube small or prominent, sometimes distinctly succulent, often persistent on desiccated flowers for a long time; corolla variously flimsy or succulent; corolla tube as long as or longer than corolla lobes, often exceeding free sepal segments in length; corolla lobes generally slightly to distinctly recurved; stamens usually inserted in middle of corolla tube or higher up; filaments often short, thin; anthers included or well-exserted; nectar scales generally wider than long. Chromosome number (basic): x = 18.

Kalanchoe subg. Calophygia is naturally endemic to Madagascar (Descoings 2007). However, K. beharensis Drake del Castillo (1903: 41) has a tendency to become naturalised in places well away from its natural distribution range in southern Madagascar (see for example Raymond-Hamet 1941: 489, Conte 2004: 40, 67, Smith et al. 2019: 247 and map under Fig. 12.18.2, and Smith et al. 2021b: 55). The only known stoloniferous kalanchoe, K. synsepala Baker (1882: 110) , is included in K. subg. Calophygia.

The taxonomy of the subgenus was reviewed in Smith (2023e).

B.4 Kalanchoe subg. Kitchingia (Baker) Smith & Figueiredo (2018b: 169) .

Basionym :— Kitchingia Baker (1881: 268) .

Type:— Kitchingia gracilipes Baker (1881: 268) (lectotype), designated by Smith & Figueiredo (2018b: 169), accepted name Kalanchoe gracilipes (Baker) Baillon (1885: 469) .

Homotypic synonyms:— Kalanchoe [unranked] Kitchingia (Baker) Baillon (1885: 468) ; Kalanchoe sect. Kitchingia (Baker) Boiteau (1947: 7) , pro parte; Bryophyllum Salisbury (1805 : t. 3) subg. Kitchingia (Baker) Byalt (2008: 462) , pro parte.

Heterotypic synonym:— Kalanchoe subg. Calophygia Descoings (2006: 24) , pro parte, excl. type.

Designation not validly published:—“ Kalanchoe subg. Kitchingia ” (Baker) Maire (1977: 263), nom. inval. ( Turland et al. 2018: Art. 41.5).

Not validly published infrasubgeneric designations applicable to taxa included in K. subg. Kitchingia :— “ Kalanchoe [sect. Kitchingia ] subsect. Sylvaticae ” Boiteau (1947: 8), nom. inval. ( Turland et al. 2018: Art. 39.1).

“ Kalanchoe [sect. Kitchingia ] [infragen. unranked] Sylvaticae ” Boiteau & Mannoni (1948a: 7), nom. inval. ( Turland et al. 2018: Art. 39.1, and see Art. 37.3).

“ Kalanchoe [sect. Kitchingia ] subsect. Campanulatae ” Boiteau (1947: 8), nom. inval. ( Turland et al. 2018: Art. 39.1).

“ Kalanchoe [sect. Kitchingia ] [infragen. unranked] Campanulatae ” Boiteau & Mannoni (1948a: 9), nom. inval. ( Turland et al. 2018: Art. 39.1, and see Art. 37.3).

Description:—Perennial, herbaceous, glabrous to pubescent, non-pruinose, pendent to erect, terrestrial or epiphytic, succulent subshrubs. Roots fibrous, plants sprouting from roots very uncommon. Stems thin, somewhat wiry, flexible. Leaves distinctly petiolate, not bulbiliferous; margins crenate. Inflorescences terminal, few-branched, sparsely-flowered, cymose, not bulbiliferous; pedicels widening towards calyx. Flowers pendent, brightly coloured; calyx short, not obscuring corolla, basally rounded; calyx tube formed by fusion of ± ½ of sepals; corolla flimsy, sometimes externally hairy; corolla tube elongated, campanulate-cylindrical, substantially longer than calyx, not constricted around ovaries; filaments internally adpressed to corolla tube, inserted above middle of corolla tube; anthers ± exserted, visible at corolla mouth; carpels small, oblong, free, distinctly divergent-spreading from base; carpels ± 3× shorter than styles; nectar scales slightly longer to slightly shorter than wide, semicircular to almost square to rectangular, never linear, slightly emarginate to indented apically. Chromosome number (basic): x = 17.

Kalanchoe subg. Kitchingia is naturally endemic to Madagascar. The taxonomy of the subgenus was reviewed in Smith et al. (2021c).

B.5 Kalanchoe subg. Alatae (Gideon F.Sm.) Smith (2023f: 64) ( Fig. 7 ).

Basionym :— Kalanchoe sect. Alatae Smith (2021: 179) .

Type:— Kitchingia uniflora Stapf (1908: 258) , currently accepted name Kalanchoe uniflora (Stapf) Hamet (1910: 52) , lectotype designated by Smith (2021: 179).

Infrageneric designations not validly published:—“ Kalanchoe [unranked] Epidendrae ” Boiteau & Mannoni (1948b: 57).

“ Kalanchoe subg. Alatae ” (Raymond-Hamet 1933: 547) Gideon F.Sm., Shtein & D.-P.Klein in Smith et al. (2021d: 255).

Description:—Perennial, small to medium-sized, epiphytic, rarely terrestrial or lithophytic, herbaceous, succulent shrublets; ± glabrous throughout. Roots fibrous, plants sprouting from roots very uncommon. Stems herbaceous, generally weak, producing thin, aerial roots. Leaves orbicular to ± cordate, obovate to slightly oblong; not bulbiliferous. Inflorescences not bulbiliferous; pedicels broadening towards flower. Flowers pendulous at anthesis, brightly coloured; corolla generally flimsy; calyx tube formed by fusion of ± ⅓ of sepals, fused portion ± horizontally spreading, free portion spreading or adpressed to corolla tube; corolla tube not obscured by calyx tube, elongated, campanulate-cylindrical, hardly spreading at level of ovary, broadest in apical ⅓, then constricted towards mouth; stamens inserted very low-down in corolla tube at ± level of carpels; filaments shorter than corolla tube; anthers ± included or at least visible at mouth; carpels about as long as styles; nectar scales linear-ribbon-like to linear-rectangular,> 2× longer than wide, distinctly indented above; seeds long, thin, winged at both ends with linear-lanceolate near-transparent tissue. Chromosome number (basic): x = 20.

Kalanchoe subg. Alatae is naturally endemic to Madagascar. The taxonomy of the subgenus was reviewed in Smith et al. (2021d).

C. A new rank for Kalanchoe subg. Pubescentes

C.1 Kalanchoe sect. Pubescentes (A.Berger) Gideon F.Sm., sect. nov. ( Fig. 8 ).

Basionym :— K. [infragen. unranked] Pubescentes Berger (1930: 404, 407, as “§ 5”).

Homotypic synonym:— Kalanchoe subg. Pubescentes (A.Berger) Smith (2024g: 280).

Type:— K. pubescens Baker (1887: 470) (see Smith 2020d: 52–53).

Designations not validly published:—“ Kalanchoe [sect. Bryophyllum ] sub sect. Centrales ” Boiteau (1947: 8), nom. inval. ( Turland et al. 2018: Art. 39.1); “ Kalanchoe [sect. Bryophyllum ] [infragen. unranked, as “§”] Centrales ” Boiteau & Mannoni (1948b: 23), nom. inval. ( Turland et al. 2018: Art. 39.1).

Nomenclatural notes:—Apart from the two designations K. sub sect. Centrales ” and “ K. [infragen. unranked, as “§”] Centrales ” not having been validly published because they lacked a Latin description or diagnosis ( Turland et al. 2018: Art. 39.1), Boiteau (1947: 8), at first, did not indicate which of the species he assigned to K. sect. Bryophyllum should be included in the not validly published “ K. subsect. Centrales ”.

Description:—Perennial or biennial, terrestrial, epiphytic, or lithophytic, herbaceous, extensively or at least sparsely pubescent, creeping to leaning to erect, succulent subshrubs. Roots fibrous, plants sprouting from roots very uncommon. Stems hard-wiry to flexuose to rigid. Leaves variously shaped, not bulbiliferous, petiolate to sessile. Inflorescence bulbiliferous, bulbil clusters dense, long-lasting; pedicels broader towards flower. Flowers pendulous to spreading, brightly coloured; calyx tube formed by fusion of ± ⅓ to ½ of sepals, fused portion ± rounded to flattened basally, free portion generally adpressed to corolla tube; corolla generally somewhat succulent, often adorned with darker, contrasting veins, often pubescent; corolla tube 4-angled to longitudinally fluted lower down, constricted there, campanulate-urceolate to cylindrical above; stamens inserted below middle of corolla tube; anthers ± exserted to well-exserted; carpels narrowly oblong, basally connivent, somewhat to much shorter than styles; nectar scales variously shaped, longer to shorter than wide, never linear, slightly indented above. Chromosome number (basic): x = 17.

Kalanchoe sect. Pubescentes is naturally endemic to Madagascar.

D. Kalanchooid subgenus previously reduced to the rank of section

D.1 Kalanchoe [subg. Kalanchoe ] sect. Raveta Smith (2022c: 210) ( Fig. 9 ).

Type:— Kalanchoe thyrsiflora Harvey (1862: 380) , designated by Smith (2022c: 210).

Homotypic synonyms:— K. [infragen. unranked] Transvaalenses Berger (1930: 404, 407, as “§ 8”) (see Turland et al. 2018: Art. 37.3).

Kalanchoe subg. Fernandesiae Smith (2020c: 5) .

Designation not validly published:—“[ Kalanchoe / Cotyledon ] sect. Raveta ” Raymond-Hamet (1916: 83–84).

Figures

FIGURE 3. The genus Kalanchoe (ca. 200 taxa; Crassulaceae subfam. Cotyledonoideae) is Madagascar-centred but otherwise widely distributedonsomeIndianOceanislands,overmuchof sub-SaharanAfrica,andintheNear,Middle,andFarEast.Kalanchoedaigremontiana Raymond-Hamet & Perrier de la Bâthie (1914: 128) is shown here. This species is a representative of K. subg. Bryophyllum. Photograph: Gideon F. Smith.

FIGURE 5. Kalanchoe klopperae Smith & Figueiredo (2022: 106), here growing well-camouflaged among forbs and grasses, is a representative of K. subg. Kalanchoe. Photograph: Gideon F. Smith.

FIGURE 6. The generally greyish white-leaved, brittle-woody shrub Kalanchoe bracteata Scott Elliot (1891: 15) is a representative of K. subg. Calophygia. Photograph: Gideon F. Smith.

FIGURE 7. Kalanchoe uniflora (Stapf 1908: 258) Hamet (1910: 52) is a representative of K. subg. Alatae (see Stapf 1909 and Smith 2024h for comprehensive discussions). Photograph: Gideon F. Smith.

FIGURE 8. The inflorescences of Kalanchoe manginii Raymond-Hamet & Perrier de la Bâthie (1912: 370) are distinctly smallbulbiliferous post-flowering through the formation of dense, long-lasting bulbil clusters. Kalanchoe manginii is a representative of K. sect. Pubescentes. Photograph: Gideon F. Smith.

FIGURE 9. The inflorescence of Kalanchoe deliae Smith (2023g: 133) is distinctly and densely club-shaped—the one shown here is spent. The pseudo-rosette that has flowered dies but plants will sprout from the base (upper left corner). Kalanchoe deliae is a representative of K. [subg. Kalanchoe] sect. Raveta. Photograph: Gideon F. Smith.