Alocasia

A garden-bred aroid, a cross between Alocasia longiloba and the kris plant (Alocasia sanderiana) raised by the French horticulturist Chantrier at Mortefontaine and named Alocasia × mortfontanensis in 1891. It is sold mostly as Alocasia amazonica or Alocasia × amazonica: NC State Extension lists that as its former name, and Singapore's National Parks Board says the amazonica name was never validly published and seems to come from Amazon Nursery, a 1950s Florida nursery, not from the Amazon. It grows from a rhizome into a clump of arrow-shaped, very dark green leaves with bold silver to lime-white veins, wavy edges and purple undersides, 1 to 4 feet tall according to NC State. Outside USDA zones 10a to 12b it is a houseplant for bright, indirect light, kept above 60°F. Every part is poisonous: the ASPCA lists Alocasia as toxic to dogs, cats and horses, and NC State says the sap can also irritate skin and eyes.

A massive evergreen aroid from southern and eastern Asia, native from India and the eastern Himalaya through Indochina to southern China, Taiwan and southern Japan, grown for its huge, glossy, upright, arrow-shaped leaves. UF/IFAS Extension gives it 4 to 8 feet tall and 4 to 6 feet wide in the garden, and the RHS says it can reach 4.9 feet as a houseplant. Its flowers are scented, most strongly at night, and Wikipedia gives night-scented lily as another of its names. Outside USDA zones 10 and warmer it lives indoors. Every part is poisonous: it is full of needle-like calcium oxalate crystals, Japan's Ministry of Health, Labour and Welfare records food poisoning when its stems were mistaken for taro, and the ASPCA lists Alocasia as toxic to dogs, cats and horses.

A clumping aroid grown as a houseplant for its glossy, deep green, heart-shaped leaves on upright green stalks. Flora of China records it from southern China to the Himalaya, Indochina and Sri Lanka, by watersides and fields, but cannot say whether it is wild or cultivated there, and the National Tropical Botanical Garden calls it probably a cultigen, always found near villages and temples. The RHS describes a tender perennial up to about 3.3 feet tall and wide that rarely flowers. Outside USDA zones 10 and warmer it lives indoors. Every part is toxic: the ASPCA lists Alocasia as toxic to dogs, cats and horses, and despite its name it is not the edible taro, Colocasia esculenta. In tropical gardens it escapes: PIER rates it high risk and records it as invasive on several Pacific islands, Hawaii among them.

A massive evergreen aroid from the rainforests of eastern Australia, found from northeast Queensland south to coastal central New South Wales, with huge, glossy, arrow-shaped leaves on long stalks and, in summer, greenish spathes around a strongly scented spadix. PlantNET, the New South Wales flora, gives it 3.3 to 5.9 feet tall with leaves to about 28 inches long. Outdoors it needs a frost-free, partly shaded, moist spot, which in USDA terms means zones 10 and warmer; elsewhere it is a large container plant. Every part is poisonous: CSIRO's rainforest key records fatal poisonings in children, Flora of Australia calls its starchy stem dangerously toxic, and the ASPCA lists Alocasia as toxic to dogs, cats and horses. Birds eat its red berries and spread it, and New Zealand lists it as an environmental weed.

A Southeast Asian aroid grown as a houseplant for its long, arrow-shaped leaves, dark green with gray-green main veins, held on tall leaf stalks that Flora of China describes as strikingly mottled chocolate-brown. The RHS calls it elephant's ear plant, a name it shares with the rest of the genus. Flora of China records it in tropical forests and thickets from southern China to Malaysia, at up to 4.9 feet tall. Plants are still sold under former species names that GRIN Taxonomy and Wikipedia now place in Alocasia longiloba, among them Alocasia lowii, A. watsoniana and A. korthalsii, and NC State Extension names it as one parent of African mask (Alocasia × mortfontanensis). Indoors except in USDA zones 10 and warmer. Every part is poisonous: the ASPCA lists Alocasia as toxic to dogs, cats and horses, and NC State Extension says the genus is poisonous if eaten and causes contact dermatitis.

A massive evergreen aroid grown for leaves that the RHS says reach 3.9 feet long, carried more or less upright on stalks up to 3.9 feet tall. Outside frost-free climates it is a big houseplant or conservatory plant, which the RHS sizes at 4.9 to 8.2 feet tall and wide; planted out in USDA zones 10 and warmer it grows much larger, and UF/IFAS gives it 12 to 15 feet. It has been grown as a starchy food crop across tropical Asia and the Pacific for so long that the Flora of China says it is not clear where, if anywhere, it still grows wild. Every part is toxic raw: the ASPCA lists alocasias as toxic to dogs, cats and horses, and the RHS warns that it is toxic if eaten and irritates skin and eyes, so where it is a food the corm and stem are eaten only after long cooking. It has naturalised along streams in Hawaii and rivers in Fiji and is cited as invasive on many Pacific islands; UF/IFAS does not consider it invasive in Florida and recommends it in place of invasive wild taro, but no elephant ear should be planted beside a natural waterway.

A compact aroid from northern Luzon in the Philippines, grown as a houseplant for its narrow, arrow-shaped leaves, deep green and velvety above with bold white veins and wavy edges. Wikipedia says its most popular cultivar is 'Frydek', which NC State Extension describes with burgundy leaf undersides. It is rare in the wild: Co's Digital Flora of the Philippines lists it as Vulnerable, and Wikipedia says overcollection made it scarce and that harvesting wild plants is illegal in the Philippines, so buy nursery-grown plants. Indoors except in USDA zones 10 and warmer. Every part is poisonous: the ASPCA lists Alocasia as toxic to dogs, cats and horses, and NC State Extension says the genus is poisonous if eaten and causes contact dermatitis.

A large aroid of India, Bangladesh, Myanmar, Vietnam and Java whose standing as a species is disputed. Kew's World Checklist and GBIF accept Alocasia indica, but the Flora of China, PROSEA and Plants For A Future treat it as a synonym of giant taro (Alocasia macrorrhizos), and the RHS lists the name as misapplied to giant taro; Aroidpedia reports that the 2019 Fascicles of Flora of India keep it as a separate species. Flowers of India, which calls it Indian taro, tells it from giant taro by its light green, slightly heart-shaped leaves with rounded basal lobes, against giant taro's arrow-shaped ones, and says it is widely grown in Manipur as a vegetable. No source rates its hardiness as a species, so this record keeps it indoors except in USDA zones 10 and warmer, the range NC State Extension gives the genus. It is toxic raw: the ASPCA lists alocasias as toxic to dogs, cats and horses, and NC State and UF/IFAS describe calcium oxalate crystals that irritate the mouth, skin and eyes.

An aroid from Northern Mindanao in the Philippines, named for its leaves, whose deeply scalloped edges recall the wavy blade of the kris dagger. It grows from an upright rhizome and carries only a few arrow-shaped leaves at a time, 12 to 16 inches long, deep glossy green to almost black, with bold white to silvery veins and margins and usually purple beneath. It is one parent of African mask (Alocasia × mortfontanensis), the hybrid sold as Alocasia amazonica. Wikipedia, citing the IUCN Red List, gives it as Critically Endangered in the wild and says collecting it there is illegal, so buy nursery-grown plants. Except in USDA zone 10 and warmer, it is a houseplant for bright, indirect light, warmth and humidity. Every part is poisonous: the ASPCA lists Alocasia as toxic to dogs, cats and horses, and the RHS says alocasias should not be eaten and that their sap can irritate skin.