Subfamily Lasioideae·Tribe Lasieae
Cyrtosperma
DESCRIPTION
Cyrtosperma is a genus of fifteen swamp and rainforest herbs of Malesia and the Pacific, placed in subfamily Lasioideae, tribe Lasieae. They are rhizomatous and usually solitary, and they range from slender plants of the forest floor to giants whose spiny, mottled petioles stand three meters tall. The blade is hastate to sagittate, and the leaves are generally all held facing the same way.
A single inflorescence rises on a peduncle built like the petiole, and the flowers are hermaphrodite along the whole length of the spadix rather than divided into male and female zones as in most aroids. The name is the seed: Greek kyrtos, curved, and sperma, seed, for the strongly campylotropous seed — reniform to orbicular to helically twisted, smooth, crested or warty. Griffith founded the genus in 1851 on a Malayan plant he called Cyrtosperma lasioides. Engler later built a broad pantropical genus on the unilocular ovary, taking in African and South American plants; Hay’s 1988 monograph dismantled it, sending those species to Dracontium, Anaphyllopsis, Urospatha and Lasimorpha. Hay recognized eleven species. Four have been added since: C. hambalii in 2001, C. timikense in 2020, and C. hayii and C. prasinispathum in 2024.
Hay declined to erect formal sections and used four informal groups instead, which later authors have kept. Two of the newest species sit awkwardly in them: C. timikense has anthers that are exserted yet was placed beside C. cuspidispathum by resemblance rather than by the key, and C. hayii was described with downward-pointing spines — a character Hay’s generic key treats as belonging to the genus’s relatives rather than to Cyrtosperma.
Every one of these names belongs to a single species, C. merkusii, the giant swamp taro, grown for its enormous corm in pits dug on Pacific atolls and in swamps through Malesia. No other species in the genus carries a common name in wide use.
DISTRIBUTION
Malesia and Oceania. All fifteen species occur in Papuasia — New Guinea and its satellite islands, Bougainville and the Solomons — and only one of them is found anywhere else. C. merkusii runs from the Malay Peninsula, Sumatra, Borneo, Java and the Philippines right across the Pacific, carried in cultivation as the giant swamp taro as far as the Society and Marquesas Islands.
That shape let Hay make a claim almost no other aroid genus can: this is the only oligotypic genus of Araceae more diverse east of Wallace’s Line than west. The centre is New Guinea, which holds thirteen of the fifteen. Hay recorded none from Sulawesi, Halmahera or Australia.
CHROMOSOMES
2 species have been counted.
2 of 15 species have a published 2n count.
What chromosome numbers mean for a cross, in the Chromosomes and Crossing guide.
Counted species (2)
Sources (3)
- Das, D.; Neog, B.; Dutta, S.; Raidongia, L.; Das, A. B.; Hatimuriya, R. 2020. Karyomorphological analysis of some edible aroids of Upper Brahmaputra Valley of Assam. Journal of Cytology and Genetics 21(NS): 27–39.
- Flach, M.; Rumawas, F. (eds.) 1996. Amorphophallus (chapter in Plant Resources of South-East Asia No 9: Plants yielding non-seed carbohydrates). Plant Resources of South-East Asia No 9: Plants yielding non-seed carbohydrates, Backhuys Publishers, Leiden 9: 45.
- Marchant, C. J. 1973. Chromosome variation in Araceae: V. Acoreae to Lasieae. Kew Bulletin 28(2): 199–210.
ECOLOGY
The genus is equatorial and, with one exception, lowland: most species grow below about 700 m in the perhumid tropics of New Guinea and the Solomons, where rain falls through the year and the swamp forests they live in rarely dry out. C. bougainvillense is the outlier, montane between 600 and 2000 m on Bougainville. At the other end of the range, C. merkusii tolerates conditions no other species in the genus faces — brackish ground where soil salinity can reach 1.5 per cent, and standing water that would rot most crops. It grows larger waterlogged than it does on dry land.
Terrestrial herbs of lowland swamp forest, rainforest undergrowth, regrowth and stream sides. The flowers are protogynous and the species studied are self-sterile. In C. cuspidispathum the stigmas turn receptive in a wave down the spadix over about two days, each carrying a drop of nectar, and stay receptive for roughly three weeks unless pollinated; pollen follows weeks later, in coherent rope-like masses. Weevils feed on the tissue inside the spathe base. Ripe fruits of that species are expelled from the spadix and left hanging by the stripped inner epidermis of the tepals, a mechanism otherwise known only in Anthurium and since seen in C. hambalii; and the geniculus at the top of the peduncle swings the whole spadix over as the fruit ripens — to pointing straight down in C. cuspidispathum, to horizontal in C. macrotum.
Araceae · Form
Morphology
Swamp herbs built on a condensed rhizome and a spiny, mottled petiole, with flowers that are hermaphrodite the whole length of the spadix rather than divided into male and female zones as in most aroids. The genus is named for its seed, and the seed is still what identifies it.
There is no stem to speak of. A thick rhizome creeps at the surface with its internodes condensed almost to nothing, and the leaves rise from it directly; in the one cultivated species it swells into a corm that can weigh seventy kilograms.
The rhizome
Hay's circumscription opens on the habit: massive to slender, usually solitary, occasionally clump-forming rhizomatous herbs. The rhizome is thick, creeping and condensed — the internodes barely lengthen, so the plant does not run, and the older parts either persist for a long time or rot away quickly depending on the species. That condensed axis is a working character, not a description. It is what separates Cyrtosperma from Podolasia of West Malesia, whose rhizome has distinct internodes, in the generic key Hay built to break up Engler's pantropical genus.
The size range within that one architecture is the range of the genus. At one end are slender plants of the forest floor; at the other, giants whose petioles alone stand three meters. Cyrtosperma merkusii covers most of the span by itself: a robust to gigantic herb to 4 m, its rhizome short and slender to very large, sometimes globose, sometimes weighing up to 70 kg in Hay's description, and weakly to freely suckering. Crop reports run heavier: Manner's 2011 production profile of giant swamp taro gives corms of up to 90 kg in Kiribati, 100 to 120 kg in some varieties left to grow for years, and about 180 kg for one corm on Pohnpei, against average weights of 2 kg on Chuuk and 4.5 kg on Yap. It is that corm, not the leaf, that made the species a staple.
Fig · The habit and the rhizome — Hay 1988, drawn by Rosemary Wise
Leaves several together on spiny, usually mottled stalks up to three meters long, each blade swung to face the same way as its neighbours by a swollen joint at the top of the petiole.
Petiole and geniculum
The petiole carries two of the genus's three diagnostic characters. It is spiny and usually mottled, and it ends in a prominent pulvinar geniculum — a swollen joint that orients the blade. The result is the habit a field botanist recognises before anything else: the leaves are generally all held facing the same way, a stand of them turned together like a crowd.
The armature is the character Hay's key leans on hardest and the one that has since given way. In his treatment Cyrtosperma has spines straight and up-turned, or all up-turned, against Podolasia, whose spines are mixed straight and down-turned, and Lasimorpha, whose angular petioles are armed in rows. Cyrtosperma hayii, described in 2024 from Southwest Papua, has downward-pointing spines — a character Hay's key treats as belonging to the genus's relatives rather than to Cyrtosperma. The character is no longer absolute.
The blade
Blades are hastate to sagittate, with the posterior lobes longer than the anterior. C. merkusii gives the measured range: petioles from about 40 cm to about 3 m, heavily armed and often very heavily so with stout conical spines toward the base, through to entirely unarmed in the cultivated forms; blade from about 30 cm to 1.3 m long and up to about 80 cm wide, armed or not beneath, held anywhere from horizontal to vertical with the posterior lobes down. Its venation changes with the size of the plant — curvinerved in the anterior lobe of small plants, pinnate in large ones — and the posterior midribs run naked in the sinus for about 5 cm.
Fig · The blade, and two petioles armed differently — Hay 1988, drawn by Rosemary Wise
One inflorescence on a peduncle built like the petiole, and flowers that are hermaphrodite along the whole spadix — no male zone, no female zone, no sterile band between them.
Spathe and spadix
The inflorescence is solitary, rarely paired, on a peduncle like the petiole and armed like it. The spathe is erect and only rarely forms a hood; its upper part is sometimes long-acuminate and spirally twisted, its lower part convolute or not, and it ranges in colour from blackish purple to white. The spadix is sessile to stipitate.
Those are not idle details. Hay declined to erect formal sections and used four informal groups instead, and the groups are built almost entirely on this organ: whether the stamens are exserted from the tepals at male anthesis (the Merkusii group), whether the upper spathe is twisted through at least a full turn or the lower spathe convolute with hexamerous flowers (the Cuspidispathum group), whether the lower spathe is convolute with tetramerous flowers (Carrii), or not convolute at all (Macrotum). Later authors have kept them.
The flowers
The flowers are hermaphrodite throughout the spadix, 6-(5-)4-tepalate and -staminate, with free filaments and wet receptive stigmas. The ovary is unilocular and multi- to uniovulate, with basal to basal-parietal placentation — and it was that unilocular ovary on which Engler built a broad pantropical Cyrtosperma taking in African and South American plants, the concept Hay dismantled in 1988.
How they work
The flowers are protogynous, and the species studied are self-sterile. Cyrtosperma cuspidispathum is the one worked out in detail: the stigmas become receptive in a rapid basipetal sequence over about two days and stay receptive for about three weeks unless pollinated, each carrying a drop of nectar; pollen follows only afterwards, released from apical pore-like slits in coherent rope-like masses, in a slow basipetal sequence over several weeks. The inflorescence smells faintly musty-fruity, day and night. Weevils, Trochorhopalus strangulatus, feed on the tissue inside the spathe base.
Cyrtosperma johnstonii is the instructive exception. It almost never sets seed in cultivation, and Hay took it in 1988 for a single clone. He revisited it in 2020: the plant does fruit, it is diploid, and it is now known from the wild, so it is not sterile. Each bloom is mechanically self-incompatible, and the clone is probably genetically self-incompatible as well.
Fig · The spadix, and the hermaphrodite flower in detail — Hay 1988 (Rosemary Wise); Beccari 1882, Tav. XXIV
The genus is named for its seed — Greek kyrtos, curved. The fruit is a berry, usually red or orange but dull purple in one Bornean form, and in at least two species the ripe one is pushed off the spadix and left hanging by a strip of tepal skin.
The fruit, and where it ends up
The fruit is a berry, usually red or orange; in the heavily armed Bornean plants sometimes kept apart as Cyrtosperma ferox it is described as ripening dull purple. In Cyrtosperma cuspidispathum, and perhaps C. kokodense, the ripe fruits are expelled from the spadix and left dangling by the stripped inner epidermis of the tepals — a mechanism otherwise known only in Anthurium. Imran has since seen the same thing in C. hambalii near Timika. In C. giganteum and C. timikense the berries protrude from the tepals but stay on the spadix.
The whole infructescence moves as it ripens. The geniculus at the top of the peduncle — the same joint that orients a leaf blade — swings the spadix over: to pointing straight down in C. cuspidispathum, to horizontal in C. macrotum.
The seed
The seed is strongly campylotropous, reniform to orbicular to helically twisted, pachychalazal, strophiolate, albuminous, and smooth, crested or warty. Griffith's genus takes its name from that curve, and Schott spelled it out in 1858: a name compounded from kyrtos, curved, and sperma, seed.
Hay used the seed harder than any other organ. It carries the generic character in his key — crested and-or warty, and if smooth then under 5 mm, against the large smooth orbicular seed of Podolasia — and it separates species within the genus: helically twisted and stony in C. bougainvillense, crested in C. merkusii, smooth in the Macrotum and Carrii groups. The measured case is C. merkusii, whose seed is 5 to 11 mm long, brown, and carries about three raised warty longitudinal crests, running to sparsely and irregularly warty and only faintly crested. Cultivated selections of that species break the pattern: their seeds are larger, less ornamented and less curved than the wild ones, and they set less fruit.
Fig · Fruits expelled and left hanging, and the curved seed — Hay 1988 (Rosemary Wise); Beccari 1882, Tav. XXIV
Araceae · Care
Cultivation
Two species are grown to any extent, for opposite reasons: C. merkusii as a staple root crop of the Pacific and of North Sulawesi, C. johnstonii as an ornamental. Almost everything below comes from the crop — a field trial in North Sulawesi, a nematode study in Yap, a descriptor list from Micronesia — and the crop is grown on a timescale no house plant is. Where the literature is silent this page says so rather than borrowing a figure from another aroid.
Swamp, not a mix that drains. This is the rare aroid for which waterlogging is the object rather than the hazard, and the field trial says so plainly: a high water table is the best cultivation environment there is for it.
In the wild these are terrestrial herbs of lowland swamp forest, rainforest undergrowth, regrowth and stream sides — ground wet through the year that does not dry out. Cultivation follows the habitat rather than correcting it. On Pacific atolls the crop is grown in pits dug down to the freshwater lens, and through Malesia in swamps and taro gardens; Hay's ecology for C. merkusii reads "lowland swamp forest, open swamps and cultivation, mostly near sea level; in cultivation dug pits and taro swamps on atolls and high islands".
What the trial measured
Mendiondo and colleagues surveyed six sites in North Sulawesi and then ran a split-plot field trial at two of them, growing three seed sources under waterlogged and relatively dry conditions. Plants grew under dry-land conditions — the species will tolerate it — but they grew bigger under waterlogging, and their corms carried greater concentrations of iron, manganese and potassium. The trial's waterlogged plots were held at 10 to 20 cm of standing water above ground level, which is the one explicit number the literature gives for how deep to flood it.
Across the survey sites, three soil measurements predicted corm size: a neutral pH, a low redox potential and low conductivity. Low redox is simply the signature of waterlogged, anoxic ground — four of the six sites measured negative — so the soil chemistry is saying the same thing the field trial says. The practical reading for anyone growing the plant is the reverse of the usual aroid advice: a pot kept wet kills a Scindapsus, and is the condition under which C. merkusii makes its largest corms.
The water in the pit
On an atoll the pit is not simply a hole dug down to the water table; the water standing in it has its own chemistry, and that chemistry moves. Thompson’s review of the Pacific literature sets out what governs it: the rainfall, the size of the island, where the pit sits in relation to the coastline, and how permeable and porous the substratum beneath it is. Drought raises the salinity. A pit that is productive in a wet year can turn saline in a dry one without anything about the planting having changed, and that, rather than any ordinary day, is what the species’ salt tolerance is actually buying against.
Nothing comparable has been published for the ornamental C. johnstonii, which is grown as a warm wet-soil plant under glass. There is no published substrate recipe for it, and this page will not invent one.
The one fertiliser trial published for the genus found no benefit at all. Wet ground did the work instead.
The North Sulawesi trial included three fertiliser regimes: no fertiliser, an inorganic NPK 20:20:20 at 3 to 5 g of nitrogen, phosphorus and potassium, and bokashi — fermented pig manure with a Trichoderma consortium. Both fertilisers were chosen because they are the ones subsidised and available to farmers there, so the test was of what a grower would actually reach for.
There was no overall impact of fertiliser application on above-ground or corm biomass. Fertiliser did move leaf length, leaf width and stalk length, and did so differently at the two sites, but none of that reached the corm. The authors' reading is that C. merkusii is adapted to low-nutrient wetland conditions and does not require fertilisation; their conclusion recommends it as a paludiculture crop partly because it performs well waterlogged without any. They add a second argument against feeding it: nitrogen-rich fertiliser applied to waterlogged soil can sharply increase nitrous oxide emissions.
That is a finding about a field crop grown for its corm, and it should be read as one. No feeding schedule has been published for a Cyrtosperma grown in a pot for its leaves.
Equatorial and, with one exception, lowland. Rain through the year, no dry season, and — in the crop species alone — a tolerance for brackish ground that no other member of the genus faces.
Elevation and climate
Most species grow below about 700 m in the perhumid tropics of New Guinea and the Solomons, where rain falls through the year and the swamp forests they live in rarely dry out. Cyrtosperma bougainvillense is the outlier, montane between 600 and 2000 m on Bougainville. Herbarium records for C. merkusii run from sea level to about 1,800 m, but the median sits near 10 m, which is the honest picture of where the genus actually lives.
Salt and standing water
C. merkusii tolerates conditions no other species in the genus meets: brackish water where soil salinity can reach 1.5 per cent, along with a wide range of soil and moisture conditions. That tolerance is why it became an atoll staple — a crop for ground where little else will grow — and it is the basis of the current interest in the species as a paludiculture crop for coastal land and peatlands with high water tables that cannot be drained. The crop is not seasonal, and it withstands strong winds.
The standing threat
The atolls that hold the crop are also where it is most exposed. Rao and colleagues, who built the Micronesian descriptor list, frame that work as a response to salt-water intrusion under a rising sea: the atolls of the Federated States of Micronesia are the diversity hot spot for this species and for the traditional knowledge attached to it, and that gene pool is the material a grower would draw on to buffer the intrusion. The tolerance above is a range, not a guarantee, and the cultivars sitting at the far end of it are the ones worth knowing.
What is not known
No temperature range, humidity figure or light prescription has been published for any Cyrtosperma as a cultivated ornamental. The genus is equatorial and lowland, which sets the expectation — constant warmth, high humidity, no cold — but the numbers a grower would want for an ornamental do not exist in the literature, and the ones circulating for other aroids do not transfer to a swamp herb. For the crop in the field, Manner's 2011 production profile of giant swamp taro gives a climate envelope with no growing trial cited: a mean annual temperature of 73 to 88 °F (23 to 31 °C), a mean maximum of 100 °F (38 °C) in the hottest month, a mean minimum of 59 °F (15 °C) in the coldest, and 50 °F (10 °C) as the lowest temperature tolerated, the last taken from the minimum temperature at Henderson Island in the Pitcairn group, where subfossil leaf fragments also suggest, indirectly, that the plant can withstand a minimum monthly mean of about 60 °F (15.5 °C).
Cormlets, and patience measured in years. New ones appear on the side of the mother corm one to two years after planting; the corm itself is ready to lift from three years in the Yap corm-rot study, though a 2011 profile of the crop reports most varieties maturing in one to two years, and it may be left for ten.
How the crop is moved
New cormlets develop from the outer surface of the mother corm as side shoots about one to two years after planting. At harvest they are cut off close to the point of attachment, and in Yap excised cormlets are the only planting material used. That matches the rhizome as Hay described it in C. merkusii — weakly to freely suckering — and it explains why the Pacific plants are cultivated selections rather than wild types: their characters (unarmed petioles, larger and less ornamented seeds, lower fruit set) travel together in a clone without any one of them separating cultivated from wild material formally.
The timescale is the thing a grower used to aroids will not expect. In the Yap corm-rot study of Murukesan and colleagues, corms are ready for harvest from three years after planting, while Manner's 2011 production profile of the crop says most varieties mature in one to two years and names a Chuukese variety, Onou maram, said to be harvestable in six months. The plant is perennial enough that a corm can stay in the ground for ten years or more — in Yap, corms from plants ten or more years old are among the most highly prized gifts that can be given to a chief at a funeral or ceremony.
How many clones there are
Propagating a crop by cutting pieces off it for centuries has produced diversity rather than uniformity. Rao and colleagues built a 37-trait descriptor list for the species — plant habit, leaves, petiole, inflorescence, root, corm and taste — and ran it over the collection at the Federated States of Micronesia pilot farm: of the 50 cultivars held there, 40 came out distinct. Four of those 36 the local growers did not separate at all, and had to be given names for the list to work. Anyone treating giant swamp taro as one plant is flattening at least three dozen.
Their working definition of maturity is the practical one and worth borrowing: a plant is mature when it carries an inflorescence, or when half its leaves have died back. After that, harvest is elastic. The corm goes on enlarging as the plant ages and stays edible for years, which is why a three-year corm and a ten-year corm are both ordinary things to lift, and why it is the ten-year one that becomes the gift.
That definition was written for the crop, and an inflorescence is not a sign of full size in every species: in cultivation, Cyrtosperma cuspidispathum can bloom well before it reaches full size. Julius Boos wrote on the Aroid-L mailing list on October 11th, 2004, that his own plant of that species bloomed at about 1.5 m (5 feet) tall and kept growing, and that a friend's seedling of the species had reportedly bloomed when only about 15 cm (6 inches) tall; on June 28th, 2007, Michael Mattlage showed the list a greenhouse plant in bloom, a juvenile about three years from seed that he named as Cyrtosperma cuspidispathum.
Seed, and why it is the harder route
The reason is floral, not horticultural. The flowers are protogynous: in C. cuspidispathum the stigmas stay receptive for about three weeks before that inflorescence sheds any pollen at all, so a lone plant cannot pollinate itself in time. The species studied are self-sterile besides. C. johnstonii is the cautionary case — long believed a sterile single clone because it almost never set seed in cultivation, and shown by Hay in 2020 to be a perfectly fertile diploid that is mechanically self-incompatible in each bloom and probably genetically self-incompatible as well. Seed needs two clones and overlapping timing.
Even then, a grower cannot always be sure the seed is pure. Julius Boos wrote on the Aroid-L mailing list on May 3rd, 2008, that photographs sent to him by at least two recipients of the seed that he and the late Lynn Hannon shared in 2004, from her plant of Cyrtosperma cuspidispathum, showed blooms with pinkish striping and spathes shorter than the species', features he associated with the few hybrid Cyrtosperma produced in Australia that she also grew in her greenhouse. He believed the plants raised from that seed were hybrids, not the pure species, and suspected that insects had carried pollen from one of those hybrids onto her plant. This was his judgment from photographs, not a determination of the plants.
One disease is documented in detail, and the plant hides it: corm rot caused by the burrowing nematode Radopholus similis, which seldom shows any above-ground symptom at all.
Corm rot
A corm rot of Cyrtosperma caused by Radopholus similis was first reported in 1987 from Yap, Palau and Guam, and by 1990 its incidence in Yap and Palau was put at least at 80 per cent. Murukesan and colleagues studied it in detail on corms from a knee-deep taro patch in Yap in 2005 and confirmed the nematode as the agent.
The symptoms are worth knowing precisely, because the plant gives so little warning. Infected plants seldom show any above-ground symptom. Inside, the rot is wet — despite the old name "dry corm rot", coined to separate it from bacterial and fungal soft rots — a loose mass of brown dead tissue around a deep brown necrotic centre where the nematodes live, and it carries a characteristic foul odour. The dead tissue opens into shallow to deep cavities that advance toward the edible centre of the corm, and shows on the outside as a perforated look on an otherwise smooth corm. Up to 50,000 nematodes were extracted from 10 g of fresh corm. The disease gets worse the longer the plant stands, which on a crop lifted at three years and often left for ten gives it a long run.
Why it travels, and what stops it
The nematode appears to spend its whole life cycle inside the plant's tissue, which is how it survives an anaerobic flooded swamp — an uncommon habitat for the species, and the reason its presence here was doubted at first. If it is truly absent from the rhizosphere, then the planting material is the vector, and planting nematode-free cormlets would stop the spread. The authors propose two routes: raise clean cormlets by in vitro micropropagation, or disinfest infected ones by heat, thermotherapy having already proved effective against R. similis in palms and in Anthurium.
Not a pest
The weevils found inside a Cyrtosperma spathe should not be read as an infestation. Trochorhopalus strangulatus feeds on the tissue inside the spathe base of a flowering plant, and Hay recorded it as part of what happens at the inflorescence, alongside the nectar drops on the stigmas and the faint musty-fruity scent held day and night. For the crop, Manner's 2011 production profile of giant swamp taro relays a few more reports, none with an incidence figure: the taro beetle Papuana huebneri boring the corm, leaf-eating Aphis gossypii, mealybugs (Pseudococcus sp. near adonium and Ferrisia virgata) and an unidentified bagworm, all in Kiribati; Pythium rot in the Trust Territory; Dasheen mosaic virus in Kiribati; and major crab damage in the Mortlock Islands. For Cyrtosperma grown as an ornamental nothing is published: a grower meeting scale, mealybugs or spider mites is meeting the ordinary glasshouse pests of any large-leaved aroid, and the pest management pages cover them.
Cyrtosperma Timeline
An interactive timeline showing the year each Cyrtosperma species was first described as Cyrtosperma (species may previously have been classified in other genera)
Cyrtosperma Species & Cultivars
Sources
The papers behind the morphology & cultivation tab
- Hay, A. (1988). Cyrtosperma (Araceae) and its Old World allies. Blumea 33(2): 427–469.
- Hay, A. (2020). Notes on the typification, origin, and fertility of Cyrtosperma johnstonii (Araceae–Lasioideae). Aroideana 43(3–4): 108–117.
- Hay, A. & Imran (2020). Cyrtosperma giganteum Engl. (Araceae–Lasioideae) found again in Papua Province, Indonesia. Aroideana 43(3–4): 4–11.
- Hay, A. & Imran (2020). A third enormous New Guinea lasioid – Cyrtosperma timikense, a new species from southern Papua Province, Indonesia. Aroideana 43(3–4): 97–107.
- Raynalta, E., Hariri, M. R. & Irsyam, A. S. D. (2024). Cyrtosperma hayii (Araceae, Lasioideae), a unique new species with downward-pointing spines from Southwest Papua Province, Indonesia. Phytotaxa 641(3): 235–237.
- Mendiondo, G., Moko, E. M., Sparkes, D. L., Rahardiyan, D., Welham, S. J. M., O'Reilly, P., Wilson, P., Thomas, M. L., Ngangi, J. & Sjögersten, S. (2024). Environmental and farming practice controls of productivity of Cyrtosperma merkusii (giant swamp taro), an underutilised wetland and potential paludiculture crop. Food and Energy Security 13(1): e490.
- Murukesan, V. K., van den Berg, E., Tiedt, L. R., Josekutty, P. C. & De Waele, D. (2005). Corm rot of giant swamp taro (Cyrtosperma merkusii) caused by the burrowing nematode Radopholus similis (Nematoda: Pratylenchidae) in the Pacific. Nematology 7(4): 631–636.
- Rao, S., Taylor, M. & Jokhan, A. (2014). A descriptor list for giant swamp taro (Cyrtosperma merkusii) and its cultivars in the Federated States of Micronesia. Telopea 16: 95–119.
- Manner, H. I. (2011). Farm and Forestry Production and Marketing Profile for Giant Swamp Taro (Cyrtosperma chamissonis). In: Elevitch, C. R. (ed.), Specialty Crops for Pacific Island Agroforestry. Holualoa, Hawaiʻi: Permanent Agriculture Resources.
- Aroid-L mailing list, Julius Boos, October 11th, 2004
- Aroid-L mailing list, Michael Mattlage, June 28th, 2007
- Aroid-L mailing list, Julius Boos, May 3rd, 2008
Complete Cyrtosperma Bibliography
Every source cited across all Cyrtosperma species, cultivar and hybrid pages
- Hay, A. 1988. Cyrtosperma (Araceae) and its Old World allies. Blumea 33: 427–469 repository.naturalis.nl CYRTOSPERMA BECCARIANUMCYRTOSPERMA BOUGAINVILLENSECYRTOSPERMA BRASSIICYRTOSPERMA CARRIICYRTOSPERMA CUSPIDISPATHUMCYRTOSPERMA GIGANTEUMCYRTOSPERMA GRESSITTIORUMCYRTOSPERMA HAMBALIICYRTOSPERMA HAYIICYRTOSPERMA JOHNSTONIICYRTOSPERMA KOKODENSECYRTOSPERMA MACROTUMCYRTOSPERMA MERKUSIICYRTOSPERMA PRASINISPATHUM
- iNaturalist inaturalist.org
- Cyrtosperma beccarianum Aroidpedia page
- Cyrtosperma bougainvillense Aroidpedia page
- Cyrtosperma brassii Aroidpedia page
- Cyrtosperma carrii Aroidpedia page
- Cyrtosperma cuspidispathum Aroidpedia page
- Cyrtosperma giganteum Aroidpedia page
- Cyrtosperma gressittiorum Aroidpedia page
- Cyrtosperma hambalii Aroidpedia page
- Cyrtosperma hayii Aroidpedia page
- Cyrtosperma johnstonii Aroidpedia page
- Cyrtosperma kokodense Aroidpedia page
- Cyrtosperma macrotum Aroidpedia page
- Cyrtosperma merkusii Aroidpedia page
- GBIF gbif.org
- Cyrtosperma beccarianum Aroidpedia page
- Cyrtosperma bougainvillense Aroidpedia page
- Cyrtosperma brassii Aroidpedia page
- Cyrtosperma carrii Aroidpedia page
- Cyrtosperma cuspidispathum Aroidpedia page
- Cyrtosperma giganteum Aroidpedia page
- Cyrtosperma gressittiorum Aroidpedia page
- Cyrtosperma hambalii Aroidpedia page
- Cyrtosperma johnstonii Aroidpedia page
- Cyrtosperma kokodense Aroidpedia page
- Cyrtosperma macrotum Aroidpedia page
- Cyrtosperma merkusii Aroidpedia page
- Hariri, M.R., Irsyam, A.S.D., Ariati, S.R., Raynalta, E., Setyanti, D. & Supriyatna, I. 2024. Cyrtosperma prasinispathum: a new fascinating Aroid species from Papua, Indonesia. Webbia 79(2): 291–294 doi.org
- Alderwerelt van Rosenburgh, C.R.W.K. van. 1920. New or noteworthy Malayan Araceae. Bulletin du Jardin Botanique de Buitenzorg sér. 3, 1: 374–375 archive.org
- Engler, A. 1911. Araceae-Lasioideae. Das Pflanzenreich IV.23C: 17–20, fig. 6 archive.org
- Engler, A. 1910. Araceae. Nova Guinea 8(1): 249 archive.org
- Raynalta, E., Hariri, M.R. & Irsyam, A.S.D. 2024. Cyrtosperma hayii (Araceae, Lasioideae), a unique new species with downward-pointing spines from Southwest Papua Province, Indonesia. Phytotaxa 641(3): 235–237 doi.org
- [Moore, T. & Masters, M.T.] 1876. The Brussels exhibition. Gardeners' Chronicle n.s. 5: 603 archive.org
- André, E. 1880. Alocasia Johnstoni. L'Illustration Horticole 27: 133–134, Pl. CCCXCV biodiversitylibrary.org
- Aroid-L mailing list, Julius Boos, May 3rd, 2008 hort.net
- Aroid-L mailing list, Julius Boos, October 11th, 2004 hort.net
- Aroid-L mailing list, Michael Mattlage, June 28th, 2007 hort.net
- Athens, J. Stephen & Janelle Stevenson. 2012. Pohnpei Coring Records: the Natural Distribution of Cyrtosperma chamissonis. Journal of Pacific Archaeology 3(1): 35–48. doi.org
- Beccari, O. 1882. Malesia 1: 279–280, Tav. XXIV; 303 archive.org
- Brown, N.E. 1882. Cyrtosperma Johnstoni, N.E.Br. Gardeners' Chronicle n.s. 18: 808 archive.org
- Brown, N.E. 1914. Cyrtosperma Johnstoni. Curtis's Botanical Magazine ser. 4, 10: t. 8567 biodiversitylibrary.org
- Erlinawati, I., Abinawanto, Salamah, A. & Rugayah. 2018. Genetic diversity analysis of daluga (Cyrtosperma merkusii) using Sequence-Related Amplified Polymorphism in Siau, Sangihe and Talaud Islands, North Sulawesi, Indonesia. Biodiversitas 19: 2374–2380 doi.org
- Griffith, W. 1851. Notulae ad Plantas Asiaticas 3: 149–150; Icones Plantarum Asiaticarum 3: t. 169 — Cyrtosperma and C. lasioides archive.org
- Hasskarl, J.K. 1844. Catalogus plantarum in Horto botanico Bogoriensi cultarum alter: 59 archive.org
- Linden, L. & Brown, N.E. 1892. Cyrtosperma ferox. L'Illustration Horticole 39: 59–60, Pl. CLIII biodiversitylibrary.org
- Merrill, E.D. 1914. An enumeration of the plants of Guam. Philippine Journal of Science 9C: 65 archive.org
- Moore, J.W. 1933. New and critical plants from Raiatea. Bernice P. Bishop Museum Bulletin 102: 22 hbs.bishopmuseum.org
- Nadeaud, J. 1897. Sur quelques plantes rares de Tahiti. Journal de Botanique (Morot) 11: 116–118 biodiversitylibrary.org
- Naksuriya, O. et al. 2022. Hydrolyzed flavonoids from Cyrtosperma johnstonii with superior antioxidant, antiproliferative and anti-inflammatory activity. Molecules 27: 3226 doi.org
- Ridley, H.N. 1925. The Flora of the Malay Peninsula 5: 126–127, fig. 216 biodiversitylibrary.org
- Schott, H.W. 1857. Aroideen-Skizzen. Oesterreichisches Botanisches Wochenblatt 7: 61–62 biodiversitylibrary.org
- Schott, H.W. 1858. Genera Aroidearum: 84, t. 84. Vienna archive.org
Chromosome counts
The 3 papers behind the published chromosome numbers on the Cyrtosperma pages and in the genus's Chromosomes section.
- Das, D.; Neog, B.; Dutta, S.; Raidongia, L.; Das, A. B.; Hatimuriya, R. 2020. Karyomorphological analysis of some edible aroids of Upper Brahmaputra Valley of Assam. Journal of Cytology and Genetics 21(NS): 27–39.
- Flach, M.; Rumawas, F. (eds.) 1996. Amorphophallus (chapter in Plant Resources of South-East Asia No 9: Plants yielding non-seed carbohydrates). Plant Resources of South-East Asia No 9: Plants yielding non-seed carbohydrates, Backhuys Publishers, Leiden 9: 45.
- Marchant, C. J. 1973. Chromosome variation in Araceae: V. Acoreae to Lasieae. Kew Bulletin 28(2): 199–210.