Araceae · Identification

IDENTIFYING ALOCASIA

The prior question: is the plant a species at all?

by Robert Wainblat

The Guide

Most of them are not species

Every other page in this section helps you work out which species a plant is. For Alocasia that is usually the second question, and asking it first is why so many identifications in this genus go wrong. The first question is whether the plant is a species at all.

Of the 331 Alocasia entries the Aroid Archive lists, 118 are species. The other 213 are hybrids and cultivars — named plants that exist in cultivation and have no place in any key to wild species.

  • 331 Alocasia entries the Archive lists
  • 118 of them that are species
  • 213 that are not
  • 9 that are cultivars of hybrids

What those numbers are, exactly

They are a reading of the Archive's own published feed, taken on 29 August 2026. They will drift as plants are added, and the last of them is worth a second look: nine of the entries are cultivars of hybrids — a selected clone of a cross between two species, which is two removes from anything a key contains.

The genus itself holds in excess of a hundred species in the wild1. So the cultivated population and the wild genus are roughly the same size, and they are not the same set of plants. Most of what is grown is not a subset of what is described — it is a parallel population, made deliberately, most of it within living memory.

Why this changes the order of operations

A key to wild Alocasia has no way to say this is not a wild plant. Run a garden hybrid through one and it returns a species name, confidently, having compared real characters correctly.

On these proportions, the single most likely outcome of keying a cultivated Alocasia without first asking whether it is a species is a wrong answer that looks right. Not because the key failed — because it was asked a question it cannot refuse.

Where this sits

Alocasia Morphology is the companion and it is unusually complete: the map of the blade, the venation hierarchy, the margin and its glands, the sinus, the shoot — and then a part on reading with judgment that covers provenance, the difference between observing a character and diagnosing with it, and how to argue against your own identification. Everything this page assumes about examining a plant is there.

Aroid Identification is the general account, and its Part IV sets out what species, hybrids and cultivars are, how the typography works, and what a trade name does — using Alocasia for its examples, because this is the genus where the distinction bites hardest. That material is not repeated here.

What follows is the part neither of them covers: how to tell, on the plant in front of you, which of those three you are holding — and what to do once you know.

Part I

Which of the three you are holding

The hub explains what species, hybrids and cultivars are. The harder question is which one is in the pot — and in this genus the cultivated population has a shape that helps, because it was manufactured, deliberately, from a short list of parents.

A few species make most of the hybrids

The Aroid Archive lists 154 named Alocasia crosses with a recorded parentage. Count how often each species turns up as a parent and the concentration is immediate.

Species used as a parent Crosses it appears in
Alocasia longiloba 44 of 154
Alocasia odora 31
Alocasia baginda 23
Alocasia sanderiana 16
Alocasia reginula 15

Five species out of more than a hundred in the genus, and they account for most of what is grown under a quotation-marked name. A plant whose parentage includes longiloba, odora or baginda is not unusual; it is the ordinary case.

What a published cross looks like

Parentage is only knowable when someone publishes it. Here are five that were, established in print in 2010 with the crosses their introducer supplied2 — shown under the names the site uses now.

Current name Cross Published in 2010 as
Alocasia ‘Brisbane Blue’ Alocasia brisbanensis × Alocasia odora ‘Blue’ ‘Brisbane Blue’
Alocasia ‘Regal Shields’ Alocasia reginula × Alocasia odora ‘Shimmering Velvet’
Alocasia ‘Robudora’ Alocasia odora × Alocasia robusta ‘Purple Moon’
Alocasia ‘Sarawak Moon’ Alocasia odora × Alocasia sarawakensis ‘Sarawak Moon’
Alocasia ‘Nyctedora’ Alocasia odora × Alocasia nycteris ‘Manta Ray’ — but see below

And the method is stated in the descriptions

Four of those five entries sell the cross on the same thing. ‘Shimmering Velvet’ is much hardier and easier to grow than Alocasia reginula. ‘Sarawak Moon’ is hardier than Alocasia sarawakensis. ‘Manta Ray’ is much hardier and easier to grow than Alocasia nycteris. ‘Purple Moon’ has very little or none of the finicky nature for which Alocasia robusta is infamous2.

Take a species people want and cannot grow, and cross it with one they can. That is the method, in the breeder's own words.

Both ends of that method have a first-hand account behind them. Peter Boyce wrote on July 15th, 2009, that in cultivation Alocasia robusta needs nearly full sun or very light shade and a mineral soil, and invariably reacts very badly to transplanting; the only way found to grow it successfully was to plant ex vitro plants into the final-size pot, or to sow three or four seeds in the final-size pot or final growing place.13 A plant sold under that name that takes transplanting in stride does not behave as he describes the species — evidence of the kind the diagnostic below weighs. At the other end, Steve Lucas reported on April 2nd, 2009, that a single small Alocasia odora he was given in 1996 multiplied until plants had to be dug up and discarded every summer.14

Four small, almost black, velvety heart-shaped leaves in a clay pot seen from above, each crossed by bold silver-white veins
The one people want. Alocasia reginula — small, near-black, the veins painted on in silver. It is also the species the 2010 description of its own hybrid calls harder to keep than the cross made from it.2
A single very large plain green leaf, glossy and quilted, held on a thick stalk in a dense stand of the same plant
The one that grows. Alocasia odora: big, plain, green, and hard to kill. It is a parent in 31 of the 154 crosses the Archive lists — second only to Alocasia longiloba.
Several very large dark bronze-black leaves with pale green veins, carried on long upright stalks beside a window
And the cross. Alocasia ‘Regal Shields’ — Alocasia reginula × Alocasia odora, published in 2010 as ‘Shimmering Velvet’.2 The coloring of the first plant at the size and constitution of the second. Read the three together and the method is not hidden: it is the product description.

Which gives you a diagnostic you can use today

If a plant sold to you as a difficult species is growing easily, that is evidence — not proof, but real evidence — that it is not that species.

The velvet-leaved plant thriving on a windowsill may be Alocasia reginula. It may also be half Alocasia reginula and half something chosen precisely so that it would thrive there. Vigor is the character the cross was made for, and it is the one character no key to wild species records.

A cross name fixes the parents, not the plant

Ron Weeks bought many seedlings of Alocasia ‘Portora’ and Alocasia ‘Calidora’ and grew them out. He reported on April 3rd, 2000, that they ranged from lance-leaved miniatures to broad-leaved giants, and that the petioles and veins of the ‘Portora’ seedlings ran from reddish to pale yellow. With the help of Jim Georgusis he chose two ‘Portora’ forms, a red and a green, and one ‘Calidora’ form for tissue culture.15 A plant sold under either name may be an unselected seedling or one of those selections, and the name alone does not say which.

The names move, and faster than botanical ones

Look at the third column of that table again. In the fifteen years since those five were published, three of the five have parted company with the name they were given — and they did it in two different ways.

Two were renamed, and the old name was kept as a pointer. ‘Purple Moon’ became ‘Robudora’ and ‘Shimmering Velvet’ became ‘Regal Shields’. Both superseded names are recorded against the current entry as synonyms, which is the useful part: a plant that came to you labeled ‘Shimmering Velvet’ is still findable under that label, and it will lead you to the plant it is now called.

The third did not get renamed at all, and that case is worse.

And one name is now attached to a different cross

Alocasia ‘Manta Ray’ was published in 2010 as Alocasia odora × Alocasia nycteris2. A plant under that name today is recorded as Alocasia macrorrhizos ‘Borneo Giant’ × Alocasia nycteris — a different cross, sharing one parent.

Which of those is right is not the point here. The point is that the label moved and the plant behind it changed. Botanical names are governed by a code with rules of priority and typification. Trade and cultivar names are not governed the same way, and they can be reassigned, retired and reused with nothing obliging anyone to write it down. Where the old names above survive as synonyms, that is somebody choosing to keep the trail — not a rule being followed.

The Alocasia ‘Borneo Giant’ in that recorded cross is a moving label too. On August 14th, 1998, Alistair Hay, looking at Krzysztof Kozminski's images, wrote that the plant labeled ‘Borneo Giant’ appeared to be Alocasia longiloba ‘Korthalsii’. Kozminski replied the same day that, after two more leaves, it appeared to be a regular Alocasia ‘Amazonica’, and that it had since died.16, 17 On March 27th, 2004, Peter Boyce wrote that the original introduction under that name seemed to have been genuine Alocasia robusta, whereas nearly everything labeled ‘Borneo Giant’ that he had seen for sale in the United States was in fact a very robust form of Alocasia macrorrhizos.18 A parent given only by a quoted name is only as certain as the plant that wore the label.

And the species doing much of this work had an unsettled name

A coda, because the two halves of this section are not separate worlds. Alocasia odora — a parent in thirty-one of those crosses — needed a dedicated nomenclatural paper in 2022 to establish what its name rests on: whether its basionym Arum odorum was validly published, and what to do with a confusing synonym, Caladium odoratum, which the same paper lectotypified3.

Both problems at once

So a plant behind a fifth of the cultivated crosses in this genus was, until very recently, a plant whose own name had loose ends. The cultivated side and the wild side of Alocasia are not independent difficulties. The trade rests on the taxonomy, and the taxonomy was still moving.

Part II

If it is a species

Suppose Part I clears the plant: no cultivar name, no suspicious vigor, a wild-collected origin you can point at. Then the literature for this genus is unusually good — in some places. It is organized by region, it is mostly one author's work, and it has a hole in it exactly where a lot of material enters the trade.

The genus, by region

The treatments, as Boyce lists them in setting up his own1. The last of these is the one this page draws on; the rest are named so you know they exist.

Region Treatment
New Guinea Hay 1990, with later additions in 19941
Australasia Hay & Wise 19911
West Malesia and Sulawesi Hay 1998, with additions for Sulawesi by Yuzammi & Hay 19981
The Philippines Hay 19991
Borneo Covered by the West Malesian treatment, then added to by Hay, Boyce & Wong 1997, Hay 2000 and Boyce 20071
Thailand Boyce 20081 — and he calls it provisional. See below.

That is good coverage of Malesia, New Guinea, the Philippines and Australasia, and it is why a wild-collected Alocasia from those regions is a genuinely answerable question.

And then the gap

Where the genus is least understood

Boyce states it plainly: the genus is least well understood in the trans-Himalaya — northeastern India to southwestern China — including northern Burma, Thailand, Laos and Vietnam1. Of his own Thai account he writes that, without extensive fieldwork, it can at best be regarded as provisional1.

That is a large piece of mainland Asia, and it is not a remote corner of the genus's range. A plant of uncertain origin from that part of the world is a harder problem than the same plant from Borneo, and the difficulty is in the literature rather than in the plant.

What the key will ask you for

Briefly, because the Anthurium and Monstera guides work this through at length. The Thai key opens like this1:

1. Plants massive, pachycaul. At least 1 m tall.
  2. Sinus between posterior lobes peltate…
    3. Plant with short stolons at the base of the main stems, these stolons with tuberules at the tips; spathes greenish white — Alocasia odora

Three things, and a potted plant supplies none of them reliably. The first couplet asks whether the plant is a meter tall — a question about a mature specimen, and the morphology guide is explicit that a juvenile leaf should not be compared with descriptions drawn from fully developed plants. The third asks you to look at the base of the plant, for stolons with swellings at their tips, which in cultivation is under the soil. What follows further down the key wants the inflorescence in detail: the spathe limb, the spadix, the synandria, the number of stigma lobes, and whether the spathe limb collapses before fruiting1.

Notice where couplet 3 lands. The first species this key delivers is Alocasia odora — the plant Part I showed is one parent of every hybrid in that table. The wild genus and the cultivated one meet at the same species, from opposite directions.

Part III

What to check, and what to write down

How to examine an Alocasia is already written, and written well, next door. What this page adds is the order — and in this genus the order is the whole difference.

The order of operations

  1. Ask where it came from, and accept “unknown” as an answer

    Wild-collected with a locality, or raised in cultivation? On the proportions in the Opening this one question does more work than any character. Ask the seller before you buy, and write down what they say — including when they cannot say. Cultivation or an unknown origin does not rule out a species, though. Alocasia reginula was described from cultivated plants and was long known only in cultivation; Peter Boyce reported on November 7th, 2003, that it had been found in the wild in Borneo, and on January 25th, 2009, that it had been found on the Tabin limestones of eastern Sabah.19, 20 Of Alocasia nebula, now fairly well established in cultivation, Boyce wrote on January 25th, 2009, that its exact origin was obscure and that it was still unknown in the wild: he, Josef Bogner and, independently, Alistair Hay had each seen it planted at Semenggoh Botanical Research Centre, near Kuching, in the mid-1990s, and none of them could identify it, and none of the staff they asked was sure where it had come from.20

  2. Ask whether it is a species at all, before you ask which

    Any name in single quotes; any parentage on the label; and the vigor test from Part I — a difficult species that is growing easily is evidence, not proof, that it is not that species2. This is the step that gets skipped, and skipping it is what produces a confident wrong name. A quoted name is a reason to ask, not an answer. The name Alocasia brancifolia ‘Nishihira’ has often cropped up on the market, with no consensus on whether it is a cultivar from Japan or the species itself; Peter Boyce wrote on June 21st, 2009, that there is no such name as Alocasia nishihiri (nishihira), meaning that it has never been formally published, and that all the images of it he had seen were Alocasia brancifolia.21

  3. Only then, read the plant

    Alocasia Morphology is the method: the blade map, the venation hierarchy, the margin and its glands, the sinus and the shoot — and its part on reading with judgment, which asks you to look deliberately for the character that would argue against your identification. Use that.

  4. Route by region, then open the key

    Malesia, New Guinea, the Philippines and Australasia are well served; the trans-Himalayan mainland is not1. Part II is the map.

Writing it down

The notation for a partial determination — cf., aff., and naming a rank above species — is set out in the Anthurium guide and works the same way here. Two additions are worth making habitual in this genus:

Also record Because
Whether hybrid status is open For a plant with no provenance it usually is, and no key to wild species can close it. “Species status not established” is a true statement and a useful one.
How it grows for you Odd, and it earns its place here. Ease of growth is the character these crosses were made for2, and it is the one no botanical description records. A note that a supposedly difficult species has been trouble-free for three years is real evidence for the next person. Growth can also set a sport apart from its source plant. Alocasia ‘Polly’ is a tissue-culture sport of Alocasia ‘Amazonica’ found at Silver Krome Gardens; in Bill Rotolante's account, relayed on Aroid-L by Steve Lucas, one plant among the tissue-cultured ‘Amazonica’ liners showed heavier leaf substance, shorter petioles and slower growth than the standard plants.22 Ben Zonneveld weighed equal pieces of leaf and found 20 mg for ‘Polly’ against 14 mg for the standard ‘Amazonica’, though the DNA content was the same in both, 10.1 pg.23

The honest ceiling, for the commonest case

A nursery Alocasia with no locality and no parentage: the most that can usually be established is the genus, a resemblance to a species or a group, and an open question about hybridity.

Written down plainly, that is a record which stays true. A species name guessed from a photograph is a record that will be copied onto every cutting given away from that plant, and it will outlive the plant.

Sources

The papers behind this guide

Three papers frame the guide: one regional review that also maps the rest of the literature, one editorial listing that records what five cultivated hybrids actually are, and one short nomenclatural paper about the species that turns out to be in most of them. The regional treatments behind Part II and the Aroid-L messages behind Parts I and III follow them.

  1. Boyce, P. C. (2008). A review of Alocasia (Araceae: Colocasieae) for Thailand including a novel species and new species records from South-West Thailand. Thai Forest Bulletin (Botany) 36: 1–17. The map of the genus's literature, in its introduction — which treatment covers which region, and the statement that the genus is least well understood in the trans-Himalaya. Gives the genus as in excess of 100 species, carries the Thai key quoted in Part II, and describes its own account as provisional in the absence of extensive fieldwork.
  2. Cultivar Name Establishment. Aroideana 33: 267–270 (2010). The parentages in Part I. An editorial listing of cultivar names established at their introducers' request, with descriptions supplied by them. Five Alocasia cultivars appear, all introduced by the same person, and in this paper all five have Alocasia odora as one parent. Four of the five descriptions sell the cross explicitly on being hardier or easier to grow than the other parent. Also states the rule that a cultivar name must be established in a dated hard-copy publication. ⚠ Three of the five names have changed since, and one of them, ‘Manta Ray’, now carries a different cross. Part I shows the mapping and links the current entries.
  3. Ma, Z. et al. (2022). On the Nomenclature of Alocasia odora (Araceae). Harvard Papers in Botany 27(2): 161–163. doi:10.3100/hpib.v27iss2.2022.n4 Why Part I ends where it does. The species behind every hybrid in that table needed a paper of its own to settle what its name rests on — the valid publication of its basionym Arum odorum, and the correct epithet of a confusing synonym, Caladium odoratum, which is lectotypified here.
  4. Hay, A. (1990). Aroids of Papua New Guinea. Christensen Research Institute Publication 10. Christensen Research Institute, Madang. The New Guinea treatment in the table of regional treatments in Part II.
  5. Hay, A. (1994). Alocasia simonsiana, a new species of Araceae from New Guinea. Blumea 38(2): 331–333. The 1994 addition to the New Guinea treatment in Part II.
  6. Hay, A. & Wise, R. (1991). The genus Alocasia (Araceae) in Australasia. Blumea 35(2): 499–545. The Australasian treatment in Part II.
  7. Hay, A. (1998). The genus Alocasia (Araceae–Colocasieae) in West Malesia and Sulawesi. Gardens' Bulletin Singapore 50(2): 221–334. The treatment for West Malesia and Sulawesi in Part II, and the one the Borneo additions build on.
  8. Yuzammi & Hay, A. (1998). Alocasia suhirmaniana (Araceae–Colocasieae): a spectacular new aroid from Sulawesi, Indonesia. Telopea 7(4): 303–306. The Sulawesi addition in Part II.
  9. Hay, A. (1999). The genus Alocasia (Araceae–Colocasieae) in the Philippines. Gardens' Bulletin Singapore 51(1): 1–41. The Philippine treatment in Part II.
  10. Hay, A., Boyce, P. C. & Wong, K. M. (1997). Alocasia melo (Plate 315). Curtis's Botanical Magazine 14(2): 82–86. The first of the Borneo additions in Part II: the description of Alocasia melo.
  11. Hay, A. (2000). Alocasia nebula (Plate 381). Curtis's Botanical Magazine 17(1): 14–18. The second Borneo addition in Part II: the description of Alocasia nebula.
  12. Boyce, P. C. (2007). Studies on the Alocasia Schott (Araceae–Colocasieae) of Borneo: I. Two new species from Sarawak, Malaysian Borneo. Gardens' Bulletin Singapore 58(2): 141–154. The third Borneo addition in Part II.
  13. Aroid-L mailing list, Peter Boyce, July 15th, 2009. What “finicky” means for Alocasia robusta in cultivation, in Part I: nearly full sun or very light shade, a mineral soil, and no transplanting. A reply to a list member's question about growing the species.
  14. Aroid-L mailing list, Steve Lucas, April 2nd, 2009. How fast Alocasia odora multiplied for one grower, in Part I: a single small plant given to him in 1996. A reply to a list member's question about rooting cuttings.
  15. Aroid-L mailing list, Ron Weeks, April 3rd, 2000. The spread among bought seedlings of Alocasia ‘Portora’ and Alocasia ‘Calidora’ in Part I, and the forms chosen for tissue culture. The account of the grower who bought and grew out the seedlings.
  16. Aroid-L mailing list, Alistair Hay, August 14th, 1998. The identification in Part I of a plant labeled Alocasia ‘Borneo Giant’ as Alocasia longiloba ‘Korthalsii’. Made from a list member's images, in the words “appears to be”.
  17. Aroid-L mailing list, Krzysztof Kozminski, August 14th, 1998. The owner's reply in Part I: after two more leaves the plant appeared to be a regular Alocasia ‘Amazonica’, and it had since died. One plant, as its owner saw it.
  18. Aroid-L mailing list, Peter Boyce, March 27th, 2004. What the name ‘Borneo Giant’ covered, in Part I: an original introduction that seemed to be Alocasia robusta, and nearly everything he had seen for sale in the United States being a very robust form of Alocasia macrorrhizos. One writer's observation, not a survey.
  19. Aroid-L mailing list, Peter Boyce, November 7th, 2003. The report in Part III that Alocasia reginula had been found in the wild in Borneo. A passing remark in a reply on another subject.
  20. Aroid-L mailing list, Peter Boyce, January 25th, 2009. The Tabin limestones record for Alocasia reginula and the sightings of Alocasia nebula at Semenggoh, in Part III. A reply to a list member who had asked how Alocasia nebula and Alocasia reginae differ.
  21. Aroid-L mailing list, Peter Boyce, June 21st, 2009. The answer in Part III on the name ‘Nishihira’: never formally published, and every image he had seen was Alocasia brancifolia. A short reply to a list member's question.
  22. Aroid-L mailing list, Steve Lucas, November 19th, 2009. The finding of Alocasia ‘Polly’ in Part III as a sport among tissue-cultured Alocasia ‘Amazonica’ liners at Silver Krome Gardens, quoted from Bill Rotolante. Relayed by a list member from his correspondence with the Rotolantes.
  23. Aroid-L mailing list, Ben J.M. Zonneveld, March 14th, 2002. The leaf weights and DNA content of Alocasia ‘Polly’ and the standard Alocasia ‘Amazonica’ in Part III. One comparison, posted to the list.