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).