ALOCASIA LONGILOBA ‘PURPLE’

DESCRIPTION: Alocasia longiloba ‘Purple’ is a selection of the form long grown as Alocasia longiloba ‘Denudata’, chosen for the deep purple underside of its leaves.¹

The blade is sagittate, with a broad, acuminate apex and clearly defined basal lobes. A prominent central midrib gives rise to branching secondary veins that contrast vividly against a glossy, dark upper surface with pinkish hues, while the underside carries a striking purple tint with raised, well-defined veins. The petiole is mottled — the field mark Straits growers used to separate this plant from the one sold as Alocasia lowii, whose petiole stays a clean light green.⁵

HISTORY: The form carries two names from two eras. It reached Europe from Singapore with Jean Linden in the mid-1860s, and first appeared in print as a single sentence in the report of the exhibition where Linden’s collection of new introductions took the great gold medal: “Alocasia singaporensis Linden. From Singapore. The large leaf is arrow-shaped, with large spreading basal lobes, and of dark green color.”² Fourteen years later Engler described the same plant properly as Alocasia denudata, and it is Engler’s name the trade kept.³ By strict priority the older singaporensis would win; the modern revision recommends conserving denudata instead, since the younger name is the one a century of literature actually used.⁴

The purple-backed plant behind this selection was already prized in its home range. The Straits agricultural press of 1905 recorded that “A. denudata and its variable varieties include some fine forms,” singling out one “with the back of the leaf deep purple.”⁵ Its namesake city later lost it: by 1984 Burnett judged the form “probably extinct in Singapore.”⁶

CONFUSED WITH: Despite the similarity in name, Alocasia ‘Purpley’ is a hybrid and Alocasia longiloba ‘Purple’ is a cultivar; they share only the purple coloration. Young plants of the ‘Denudata’ form are also hard to separate from ‘Lowii’, and there the mottled petiole is the tell.⁵

REFERENCES:

1. Plants of the World Online, Royal Botanic Gardens, Kew — Alocasia longiloba Miq. Plants of the World Online, Royal Botanic Gardens, Kew — Alocasia longiloba Miq.

2. Linden, J., in Gartenflora 14: 252. 1865. biodiversitylibrary.org/page/40134189

3. Engler, A. 1879. Alocasia denudata. Monographiae Phanerogamarum 2: 507.

4. Hay, A. 1998. The genus Alocasia (Araceae–Colocasieae) in West Malesia and Sulawesi. The Gardens’ Bulletin Singapore 50: 221–334. Hay, A. 1998. The genus Alocasia (Araceae–Colocasieae) in West Malesia and Sulawesi. The Gardens' Bulletin, Singapore 50: 221–334

5. Agricultural Bulletin of the Straits and Federated Malay States, n.s. 4: 261–262. 1905. Agricultural Bulletin of the Straits and Federated Malay States, n.s. 4: 261–262 (1905)

6. Burnett, D. 1984. The cultivated Alocasia. Aroideana 7(3–4): 68–162.