Air plant (Kalanchoe pinnata, (Lam.) Pers. 1805)

Identity

Air plant (Kalanchoe pinnata (Lam.) Pers., 1805) is a perennial succulent in the genus Kalanchoe, family Crassulaceae. ^{1 2}

Jean-Baptiste de Lamarck first described the species as Cotyledon pinnata in 1786. Christiaan Hendrik Persoon transferred it to Kalanchoe in 1805. At the same time, Richard Anthony Salisbury described it as Bryophyllum calycinum, establishing the genus Bryophyllum, a name still encountered in its synonymy. ¹

Names such as Life plant and Leaf of life, alongside the Caribbean names chou de Faffe and zèb maltèt, refer to its ability to produce new plantlets from a detached leaf without soil contact. Cathedral bells is another established name for the same succulent. ⁶

Recognition

An upright succulent, Kalanchoe pinnata has a cylindrical, fleshy, hollow stem reaching 1–1.5 m (3–5 ft), often reddish when young. Its opposite, thick, fleshy leaves measure 10–30 cm (4–12 in) long. A scalloped or saw-toothed edge distinguishes them from most other potted Crassulaceae. ²

Adventitious buds appear between the teeth along the leaf edge and develop roots and leaves before the leaf falls. A single leaf on the ground can produce several young plants within weeks, explaining the speed with which Kalanchoe pinnata colonizes bare ground. ⁶

At the stem tip, a panicle bears hanging flowers with tubular corollas up to 5 cm (2 in) long. They are yellowish with red-purple streaks inside and red-orange outside. Depending on climate, flowering may extend through much of the year. ²

Useful taxonomy

Although Kalanchoe pinnata is the accepted scientific name, several synonyms remain in use. These overlap with a separate genus still recognized in some toxicological and veterinary literature:

• Bryophyllum pinnatum (Lam.) Oken, 1841, a widely used synonym
• Bryophyllum calycinum Salisb., 1805, another historical name
• Cotyledon pinnata Lam., 1786, the basionym
• Kalanchoe pinnata var. brevicalyx Raym.-Hamet & H.Perrier, a name included in the synonymy
• Kalanchoe pinnata var. calcicola H.Perrier, another name included in the synonymy

The synonym Bryophyllum pinnatum remains more than a taxonomic relic. McKenzie and Dunster’s study of cattle poisoning, like much toxicological literature, uses it because some botanists continue to recognize Bryophyllum. On a label or in a scientific paper, it denotes the same plant as Kalanchoe pinnata. ^{1 7}

Habitat and range

Native only to Madagascar, Kalanchoe pinnata grows in dry, rocky habitats, waste ground and woodland edges, from sea level to nearly 2,600 m (8,530 ft), depending on the region. ²

Ornamental and medicinal cultivation carried it beyond Madagascar. It subsequently naturalized across most tropical and subtropical regions, including South and Southeast Asia, Africa, Australia, the Americas and Pacific islands. ⁶

Invasive populations are recorded in Mauritius and Réunion, notably around Étang-Salé, and in French Polynesia, where territorial regulations recognize a threat to local biodiversity. French overseas territories apply their own classifications. Hawaii also regards the species as invasive, and the Florida Invasive Species Council lists it in Category II. ^{5 4}

Metropolitan France generally confines Air plant to pots or conservatories. It needs protection below 10 °C (50 °F), and frost rapidly destroys its succulent tissues. ⁶

Life cycle and reproduction

Leaf-borne plantlets dominate reproduction in this species. Each leaf produces dozens of marginal bulbils, tiny plants already equipped with roots and leaves, which detach at the slightest touch and root when they reach moist growing medium. ⁶

Sexual reproduction also occurs: follicles 10–15 mm long contain numerous obovoid seeds about 1 mm long. It plays a secondary role compared with rapid spread through plantlets. ²

Placing a mature Kalanchoe pinnata leaf on well-drained growing medium can produce new plants in a few weeks, without rooting hormone or preliminary cutting. ⁶

Uses and risks

Traditional medical systems in French Guiana, the Caribbean, South Asia and Southeast Asia have long used Kalanchoe pinnata leaves for fever and inflammation. ⁶

Documented toxicity accompanies those traditional uses. The plant contains bufadienolides, cardiac glycosides including bryophyllin A. Their biological activity has also been investigated for antitumor effects in laboratory studies. ⁸

In cattle, eating the flowers has been documented as a cause of death. An Australian study recorded 41 poisoning episodes involving 379 cattle in Queensland between 1960 and 1984, with damage to heart muscle as the main lesion. ⁷

For household pets, the ASPCA lists Kalanchoe as toxic to cats and dogs, causing vomiting, diarrhea and, more rarely, abnormal heart rhythms. Caution therefore matters both indoors and in gardens, despite the traditional medicinal use of its leaves. ³

Varieties, look-alikes and related plants

Stable cultivars with commercial names are uncommon. The most sought-after form has irregular cream variegation and is sold as Variegata, distinct from the entirely green typical form.

Other members of the genus most often confused with Air plant include:

• Kalanchoe daigremontiana, with narrower triangular leaves, often called Mother of thousands;
• Kalanchoe delagoensis, with tubular leaves bearing plantlets at their tips rather than along the edges;
• Kalanchoe blossfeldiana, a smaller plant grown for clusters of colorful flowers and lacking leaf-borne plantlets.

Compare the leaf edges to separate these plants: among the plants discussed here, Kalanchoe pinnata combines a broad, fleshy leaf with rows of plantlets along its teeth. ²

Main sources

• Plants of the World Online / Kew, Kalanchoe pinnata (Lam.) Pers.
• GBIF, Kalanchoe pinnata (Lam.) Pers.
• ASPCA, Kalanchoe toxicity entry
• Atlas of Florida Plants, Kalanchoe pinnata
• Espèces Envahissantes Outre-mer, Kalanchoe pinnata
• Pl@ntUse / PlantNet, Kalanchoe pinnata
• McKenzie & Dunster, 1986, Bryophyllum poisoning of cattle
• Supratman et al., 2001, anti-tumor-promoting bufadienolides from Kalanchoe pinnata