Key to the Genera of Araceae

The following interactive key is based on the key in The Genera of Araceae ( Mayo, Bogner and Boyce, 1997 ).

Click on 📌 to highlight and compare characteristics.
Click on the line numbers to select characteristics.

┌1A.

Plants free-floating aquatics; leaves rosulate, hairy; flowers unisexual, naked; inflorescence with a single female flower and a few male flowers . 105. 📌Pistia

├1B.

Plants terrestrial or s, climbing hemis, s or s or other, but never floating

│

┌2A.

Leaves not differentiated into and blade, primary strictly ; inflorescence borne on a culm-like axis

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┌3A.

Leaves , ; solitary, pseudolateral and overtopped by a single, erect, leaf-like ; flowers 3-merous, s .6. 📌Acorus (Acoraceae)

│

└3B.

Leaves dorsiventrally flattened, bifacial; flowering shoot with long culm-like axis, bearing numerous spadices distally, these borne in axillary clusters ed by elongate bracts; flowers 2-merous, s 4 .1. 📌Gymnostachys

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├2B.

Leaves with distinct and expanded blade, primary never strictly

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┌4A.

Flowers with obvious of free or fused s (except Pycnospatha which lacks , but has leaf, tuberous stem and boat-shaped, - see lead 22)

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┌5A.

Flowers bisexual, uniform in appearance with flowers of only one type

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┌6A.

Higher order leaf ; tissues with abundant s

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┌7A.

; s free or ; 2-4-; s 2-8 per , axile .9. 📌Spathiphyllum

│

└7B.

; s ; 1-; s several, .10. 📌Holochlamys

│

├6B.

Higher order leaf clearly d; tissues without s or s very few

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┌8A.

Stem aerial, not tuberous or rhizomatous, never ; plant usually a climbing hemi or , less often or terrestrial, only very rarely (some spp. of Anthurium)

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┌9A.

Neotropical plants; seeds with copious ; pollen usually , never mono .8. 📌Anthurium

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├9B.

Palaeotropical plants; seeds without ; pollen mono or

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┌10A.

transversely ; s always 4 per flower; pollen ; consisting of a single cup-like structure .11. 📌Anadendrum

│

├10B.

hemispheric to discoid; s usually 6 per flower; pollen mono; usually consisting of free s or when and cup-like the flowers are borne on short pedicels

│

┌11A.

3-; s 1-; flowering shoot with inflorescences always axillary

│

┌12A.

Flowers ; s free, very rarely ly united .5. 📌Pothos

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└12B.

Flowers ; s .6. 📌Pedicellarum

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└11B.

1-; flowering shoots terminating in a branching system of spadices .7. 📌Pothoidium

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├8B.

Stem typically subterranean, tuberous or rhizomatous, sometimes aerial and creeping or scrambling but then ; plant frequently a

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┌13A.

Plants of temperate regions (N. America, NE. Asia); leaf blade always entire, to

│

┌14A.

2-; s 2 per , axile .3. 📌Lysichiton

│

├14B.

1-; 1, or

│

┌15A.

; inconspicuous; cylindric, very long .2. 📌Orontium

│

└15B.

; thick, , enclosing ; , short .4. 📌Symplocarpus

│

├13B.

Plants of tropical and subtropical regions; leaf blade , , or

│

┌16A.

Leaf deeply , division not or

│

┌17A.

many- to 2-, rarely 1-; seeds with

│

┌18A.

Plants without stolons; spines dispersed; filaments free; tropical Asia to Oceania .26. 📌Cyrtosperma

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└18B.

Plants with long stolons; spines in ridges; filaments free or ; tropical West Africa .27. 📌Lasimorpha

│

├17B.

1-, rarely 2-; seeds without or rarely with a little

│

┌19A.

, with obvious spines; Malay Archipelago .28. 📌Podolasia

│

├19B.

smooth to scabrid-, never ; tropical America

│

┌20A.

Leaf blade never ; , very long- and usually spirally twisted; s with (1-)2 to several s; neotropics .30. 📌Urospatha

│

└20B.

Leaf blade often perd with a few perforations of irregular size between primary lateral s; ; endemic to Brazil (coastal Bahia and Espirito Santo) .22. 📌Dracontioides

│

├16B.

Leaf blade , , or sometimes � pedatifid; division always ly divided, either , or yet more highly divided

│

┌21A.

Stem , aerial and scrambling to prostrate, internodes distinct, green.29. 📌Lasia

│

├21B.

Stem not , subterranean, internodes very abbreviated, not green

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┌22A.

Leaf blade , division bi or yet more highly divided; stem a depressed-globose tuber;

│

┌23A.

Tropical America; flowers with of 4-8 free s; berries smooth, red .21. 📌Dracontium

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└23B.

Tropical southeast Asia; flowers without ; berries , dark green .24. 📌Pycnospatha

│

├22B.

Leaf blade , , or sometimes � pedatifid, division to ; stem a vertical or horizontal rhizome; erect, not , blade often spirally twisted ly

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┌24A.

Tropical America; testa thick, ; embryo curved .23. 📌Anaphyllopsis

│

└24B.

Southern India; testa membranous, smooth; embryo straight .25. 📌Anaphyllum

│

├5B.

Flowers unisexual, clearly divided into female zone and male zone; tropical Africa

│

┌25A.

Leaf to tri- or quadri; s free; margins free

│

┌26A.

Leaf blade ; s free .32. 📌Zamioculcas

│

└26B.

Leaf blade bi to quadri, at least in lowest e; filaments .33. 📌Gonatopus

│

└25B.

Leaf entire, to , or ; s into cup; margins ly .34. 📌Stylochaeton

│

├4B.

Flowers without perigon of free or fused s

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┌27A.

Flowers bisexual; uniform in appearance with flowers of only one type (sometimes with sterile flowers at base)

│

┌28A.

s from temperate regions of northern hemisphere; sheath with long .31. 📌Calla

│

├28B.

Climbing hemis or sometimes s or very rarely s (few Rhaphidophora) from tropical regions; sheath non- or only short

│

┌29A.

usually very short with non-annular insertion; s not present in tissues, leaf never perd or lobed; primary lateral s forming distinct submarginal .8. 📌Heteropsis

│

├29B.

well-developed with annular insertion and usually conspicuous sheath; s present in tissues, or if absent (or nearly so) then leaf with conspicuously higher order and often perd or lobed (Amydrium); primary lateral s usually not forming distinct submarginal

│

┌30A.

s rare or nearly absent; higher order leaf completely ; 1-, 1, intrusive-parietal, s 2 .13. 📌Amydrium

│

├30B.

s abundant; higher order leaf to primary lateral s, or only finest

│

┌31A.

1- or incompletely 2-

│

┌32A.

s anatropous, more than one

│

┌33A.

s numerous, superposed on 2 (rarely 3) parietal s; seeds fusiform, straight, 1.3-3.2 mm long, 0.6-1.0 mm wide.14. 📌Rhaphidophora

│

└33B.

s 2-4 (-6) at base of a single intrusive ; seeds curved, 3-7 mm long, 1.5-4.0 mm wide .15. 📌Epipremnum

│

├32B.

s amphitropous to anatropous, solitary,

│

┌34A.

Adult leaf blade entire; palaeotropics .16. 📌Scindapsus

│

└34B.

Adult leaf blade ; neotropics (Amazonia) 18. 📌Alloschemone

│

├31B.

2-5

│

┌35A.

Seeds fusiform, claviform or lenticular, less than 3 mm long, present; s (2-)3-many per ; leaf blade entire

│

┌36A.

; seeds fusiform to claviform; leaf blades thickly .20. 📌Stenospermation

│

└36B.

axile; seeds lenticular and flattened, strongly curved; leaf blades mostly membranous .19. 📌Rhodospatha

│

└35B.

Seeds globose to , 6-22 mm long, the raphe S-shaped; absent; s 2 per ; leaf blade variously shaped, often perd or or both .17. 📌Monstera

│

├27B.

Flowers unisexual; clearly divided into female zone and or intermediate male zone, flowers very rarely in longitudinal rows (Spathicarpa)

│

┌37A.

fused laterally on both sides to and entirely enclosed by it, forming a dividing the into two chambers, with a single gynoecium on one side and the male flowers arranged in 2 rows on the other; very small, seasonally dormant plants endemic to western Mediterranean .87. 📌Ambrosina

│

├37B.

free or fused to in various degrees but never fused laterally on both sides to to form two internal chambers with a single gynoecium on one side and the male flowers on the other

│

┌38A.

s of each male flower free or only the filaments

│

┌39A.

never entirely enclosed by in a "kettle" formed of margins (if margins ly then plant never aquatic)

│

┌40A.

Higher order leaf

│

┌41A.

Upper part of persisting as long as lower part; sheath lacking ; 1-many ; dehiscing by sub pores or longitudinal slits; connective usually conspicuously thickened

│

┌42A.

variously shaped, never campanulate; plants tropical American or tropical Asian; usually short, if long then female flowers in single whorl (Aglaodorum)

│

┌43A.

Plant always terrestrial, rarely aquatic, never climbing or ; inflorescences not secreting resin at ; with cell wall thickenings; 1 or incompletely 2-5 ; most tropical Asian (except Homalomena sect. Curmeria)

│

┌44A.

Seed without , embryo large; 1, or parietal

│

┌45A.

Inflorescence with short ; female flowers in spirals; stem erect to repent; ; forest plants.72. 📌Aglaonema

│

└45B.

Inflorescence with long ; female flowers in a single whorl; stem repent; parietal; on tidal mudflats.73. 📌Aglaodorum

│

├44B.

Seed with copious , embryo relatively small; s several to many, , parietal or axile

│

┌46A.

Male flower consisting of solitary overtopped by flask-shaped ; 1-, .46. 📌Furtadoa

│

└46B.

Male flower consisting of 2-6 s, s absent; incompletely 2-5 , s parietal and axile .47. 📌Homalomena

│

└43B.

Plant usually climbing or ; inflorescences secreting resin from or at ; nearly always lacking cell wall thickenings; completely 2-many , axile to ; tropical America .45. 📌Philodendron

│

└42B.

obconic to campanulate; plants from Southern Africa (naturalized in America and Asia); long, sometimes longer than leaves .77. 📌Zantedeschia

│

├41B.

Upper part of or at , lower part long-; sheath with long, (except most Schismatoglottis spp.); 1-; dehiscing by pores, connective not conspicuously thickened

│

┌47A.

s parietal; truncate.

│

┌48A.

constricted; s anatropous to hemianatropous; sheath usually not ; upper part of usually sterile .. 📌49. Schismatoglottis

│

└48B.

not constricted; s hemiorthotropous to orthotropous; sheath with long, ; fertile almost to .50. 📌Piptospatha

│

├47B.

or and ; truncate or horned

│

┌49A.

truncate; .51. 📌Hottarum

│

├49B.

horned; or and

│

┌50A.

smaller than ; upper part of sterile with a distinct of hornless sterile flowers; constricted or not; s never excavated ly.

│

┌51A.

not constricted; male flowers smooth or ; sterile flowers between male and female flowers flattened .52. 📌Bucephalandra

│

└51B.

constricted; male flowers densely ; sterile flowers between male and female flowers subcylindric .53. 📌Phymatarum

│

├50B.

as broad as ; upper part of mostly fertile to and without a distinct ; not conspicuously constricted; s all or mostly excavated ly

│

┌52A.

s all excavated; .54. 📌Aridarum

│

└52B.

Two lateral s of each male flower excavated and horned, central truncate and hornless; s (fertile s) and (apparently sterile) .55. 📌Heteroaridarum

│

├40B.

Higher order leaf

│

┌53A.

Leaf blade , leaf solitary in each growth period

│

┌54A.

usually ; at least some of the ultimate leaf lobes , truncate or shallowly bifid, s not forming regular submarginal collective on each side

│

┌55A.

long; 1- .70. 📌Anchomanes

│

└55B.

very short; 2- .71. 📌Pseudohydrosme

│

├54B.

usually smooth, sometimes but never ; ultimate leaf lobes usually -, , with primary lateral s forming regular submarginal collective s on each side

│

┌56A.

1-4-; terminal smooth, , rarely or staminodial ( absent in Amorphophallus margaritifer and A. coudercii) .79. 📌Amorphophallus

│

└56B.

always 1-; terminal staminodial, separated from male zone by naked axial region .80. 📌Pseudodracontium

│

├53B.

Leaf blade shape of various types but never ; usually several leaves present

│

┌57A.

fertile to , terminal absent

│

┌58A.

s with robust, erect stems and an crown of to (rarely trisect) leaves; tropical America .76. 📌Montrichardia

│

├58B.

Terrestrial, hemi or plants, leaf blade variously shaped; tropical Africa.

│

┌59A.

Leaf blade usually with resin canals (lines or points); plants mostly climbing hemis; boat-shaped, ly; s lacking endothecial thickenings

│

┌60A.

s absent; shoots absent; leaf blade always simple, acute to rounded at base; 1-3-; or .74. 📌Culcasia

│

└60B.

s present; shoots present; leaf blade - to , , , or to ; 1-; .75. 📌Cercestis

│

├59B.

Leaf blade lacking resin glands; plants terrestrial; � fully expanded,not ; s with endothecial thickenings

│

┌61A.

Leaf - or subtriangular, deeply or , ; green; entirely free of .69. 📌Nephthytis

│

└61B.

Leaf -, minutely ly; pure white; female zone of to .78. 📌Callopsis

│

├57B.

with � smooth terminal

│

┌62A.

s ; tropical South America

│

┌63A.

6- to 9-; leaf blade trisect to pedatisect; stem a tuber .58. 📌Zomicarpa

│

├63B.

1- to 6-; leaf blade -; stem a tuber or rhizome

│

┌64A.

slender

│

┌65A.

connective much prolonged, thread-like; stem tuberous; 1- .61. 📌Filarum

│

└65B.

connective not at all prolonged; 1-6-; stem a creeping rhizome .59. 📌Zomicarpella

│

└64B.

relatively thick and subcylindric; stem a creeping rhizome; 1- .60. 📌Ulearum

│

├62B.

s simple; temperate Eurasia and palaeotropics

│

┌66A.

with zone of sterile flowers between male and female zones, rarely with a naked axis between female and male zones of (Arum pictum) or with fertile zones contiguous (Dracunculus)

│

┌67A.

parietal to sub; leaf blade or .88. 📌Arum

│

├67B.

and/or ; leaf blade variously shaped

│

┌68A.

s and

│

┌69A.

Male zone of contiguous with female zone; leaf blade pedatifid but lobes not spirally twisted upwards .90. 📌Dracunculus

│

├69B.

Male zone of separated from female zone by subulate to filiform sterile organs; leaf blade variously shaped

│

┌70A.

covered with subulate to setiform sterile flowers; leaf blade pedatifid, lobes twisting upwards on each side .91. 📌Helicodiceros

│

└70B.

smooth; leaf blade - or - .92. 📌Theriophonum

│

├68B.

│

┌71A.

Lower margins free (except Typhonium hirsutum)

│

┌72A.

Infructescence borne above ground level, berries dark red to purple, juicy; sterile zone between male and female zones of relatively long, often partially naked; tropical and subtropical to warm temperate Asia to Australia .93. 📌Typhonium

│

└72B.

Infructescence borne at or below ground level, berries white to pale lilac, firm, not juicy; sterile zone between male and female zones relatively short and covered entirely with subulate sterile flowers; Turkey, eastern North Africa, Near East, central Asia .89. 📌Eminium

│

├71B.

Lower margins for an appreciable distance (entirely free in Biarum aleppicum)

│

┌73A.

Leaf usually solitary, blade deeply pedatifid to pedatisect; 2-several- .94. 📌Sauromatum

│

├73B.

Leaves several; blade to , or ob; 1-

│

┌74A.

Leaf blade broadly , tube septate .95. 📌Lazarum

│

└74B.

Leaf blade , , - or ob; tube not septate .96. 📌Biarum

│

├66B.

usually without sterile flowers (sometimes present in Arisaema)

│

┌75A.

several-; female zone of free from ; without a transverse separating male and female zones.

│

┌76A.

Flowers of both sexes always present in a single inflorescence; male flowers 1-androus; lower margins ; leaf blade or .86. 📌Arisarum

│

└76B.

Flowers of both sexes sometimes present in a single inflorescence, but more often with male and female flowers appearing in separate inflorescences; male flowers 2-5-androus; lower margins ; leaf blade normally trisect, pedatisect or radiatisect, rarely simple and .98. 📌Arisaema

│

└75B.

1-; female zone of to ; usually with transverse between male and female zones .97. 📌Pinellia

│

├39B.

entirely enclosed by in a "kettle" formed of margins, plants always or aquatic

│

┌77A.

Female flowers spirally arranged (pseudo-whorl in Lagenandra nairii, whorled in L. gomezii) and free; tube "kettle" with margins occupying entire tube; blade usually opening only slightly by a straight ot twisted slit; berries free, opening from base; leaf .56. 📌Lagenandra

│

└77B.

Female flowers in a single whorl, ; tube kettle occupying only lower part of tube, remainder also with margins (except Cryptocoryne spiralis), blade spreading or twisted; berries into a syncarp which opens from the ; leaf .57. 📌Cryptocoryne

│

├38B.

s of each male flower entirely into a distinct , rarely reduced to single (Colletogyne endemic to Madagascar) or s free and ly with remote globose (Gorgonidium endemic to Andean South America), or only filaments and then stellate and 5-8-lobed (Spathantheum)

│

┌78A.

s simple

│

┌79A.

, of adjacent encircling pits in the , each pit with a somewhat prominent upper margin; leaf ; Burma to India .99. 📌Ariopsis

│

├79B.

free; leaf not ; Africa, Madagascar or Americas

│

┌80A.

Higher order leaf or if then stem a creeping rhizome and plant from Amazonia (Bognera)

│

┌81A.

s anatropous; primary lateral s of leaf forming a single marginal , no submarginal collective present; plant from tropical America or continental tropical Africa.

│

┌82A.

Female zone of free; plant from tropical west and central Africa .48. 📌Anubias

│

├82B.

Female zone of entirely to ; plant from tropical America.

│

┌83A.

Female flowers each with whorl of several s; higher order leaf strictly .35. 📌Dieffenbachia

│

└83B.

Female flowers without s; higher order leaf .36. 📌Bognera

│

├81B.

s orthotropous to hemi-orthotropous; primary lateral s of leaf forming submarginal collective and 1-2 marginal s; plants from temperate eastern North America or Madagascar.

│

┌84A.

Giant herbs (to 4m) with massive pseudostem of sheaths; s of female flower free; Madagascar (also naturalized in Pemba, Zanzibar and Mascarene Is.) .85. 📌Typhonodorum

│

└84B.

Relatively small herbs (less than 1m) without pseudostem; s of female flower into a cup-like synandrodium; eastern North America .84. 📌Peltandra

│

├80B.

Higher order leaf ; stem usually a tuber, if rhizomatous then plant Madagascan

│

┌85A.

Madagascan plants; seed lacking ; 1-; leaf with primary lateral s forming submarginal collective and 1-2 marginal s on each side of blade

│

┌86A.

s either completely with marginal or only partially by filaments; bisexual flowers often present between male and female zones of the .82. 📌Carlephyton

│

├86B.

s completely into truncate or reduced to one

│

┌87A.

reduced to one , on conical filament; fertile to ; leaf blade always .83. 📌Colletogyne

│

└87B.

on a truncate ; present or not; leaf blade , , , trisect or pedatifid .81. 📌Arophyton

│

├85B.

South American plants; seed with abundant ; with more than 1 (except Spathicarpa); leaf with primary lateral s usually forming single marginal on each side, submarginal collective s usually absent

│

┌88A.

free or only female zone to

│

┌89A.

s anatropous

│

┌90A.

s 2 per ; leaf blade entire, to sub; , with terminal of s .37. 📌Mangonia

│

├90B.

s 1 per ; leaf blade entire, to sub; fertile to

│

┌91A.

Leaf blade to bi or sub; elongate; capitate or lobed; s of female flowers free ( in Taccarum caudatum) .38. 📌Taccarum

│

└91B.

Leaf blade usually , rarely entire; short and domed; deeply lobed; s of female flowers free or .39. 📌Asterostigma

│

├89B.

s orthotropous

│

┌92A.

s and elongate; leaf blade or -sect or bi or entire and �

│

┌93A.

s in female flowers filiform to sub; with free filament or not; leaf blade , or bi .40. 📌Gorgonidium

│

└93B.

s in female flowers elongate-triangular; entirely ; leaf blade entire, � .41. 📌Synandrospadix

│

└92B.

s and short and squat or very flat; s in female flowers ob or ; leaf blade pedatisect or subpalmatifid .42. 📌Gearum

│

├88B.

usually entirely to (male zone free in Spathantheum intermedium)

│

┌94A.

6-8-; female flowers below, male above; leaf blade entire or ly lobed .43. 📌Spathantheum

│

└94B.

1-; female and male flowers intermixed (2 central rows of male flowers, 2 outer rows of female flowers); leaf blade entire.44. 📌Spathicarpa

│

├78B.

│

┌95A.

Plants climbing hemis, sometimes creeping on ground in submature growth; internodes long; berries into a syncarp .67. 📌Syngonium

│

├95B.

Plants terrestrial or geophytic, rarely aquatic, not climbing; internodes very short; berries free from each other

│

┌96A.

without an (present in Hapaline appendiculata, included here, occasionally absent in Colocasia esculenta, excluded here)

│

┌97A.

completely to incompletely 2- to several- with deeply intrusive parietal s (1- with in Jasarum, Scaphispatha and a few species of Caladium and Xanthosoma); neotropical plants

│

┌98A.

s or terrestrial; leaf blade , to or pedatifid

│

┌99A.

Pollen shed in tetrads; usually laterally thickened or expanded into a diaphanous mantle; leaf blade rarely , sometimes or -sect, or pedatifid or -sect

│

┌100A.

tube , inflated; female zone of free; s normally discoid (laterally swollen) and coherent (except Xanthosoma plowmanii); s (sterile flowers) between male and female flowers well-developed, � prismatic .65. 📌Xanthosoma

│

└100B.

tube narrow, elongate; female zone of mostly to ; region thin, spreading, diaphanous, mantle-like; s (sterile flowers) betweeen male and female flowers usually irregular or fungiform, not prismatic .66. 📌Chlorospatha

│

├99B.

Pollen shed in monads; region not laterally expanded; leaf blade usually , rarely trisect, never pedatifid or -sect

│

┌101A.

tube always ; region as broad as (Caladium paradoxum has discoid, coherent regions); s (sterile flowers) between male and female flowers well-developed, prismatic; s 1-2(-3), parietal; seeds several (rarely 1-2) .63. 📌Caladium

│

└101B.

tube gaping widely at ; much narrower than ; s (sterile flowers) lacking, male and female zones contiguous; 1, ; seed solitary .62. 📌Scaphispatha

│

└98B.

Submerged aquatics; leaf blade .64. 📌Jasarum

│

├97B.

clearly 1-, s not intrusive; palaeotropical plants

│

┌102A.

s more than 1; leaf blade

│

┌103A.

Female flowers with s; not constricted; stem trunk-like or creeping .101. 📌Steudnera

│

└103B.

Female flowers without s; with 1 or 2 constrictions; stem tuberous, producing erect or spreading stolons bearing small tubercles covered in hooked scales .102. 📌Remusatia

│

└102B.

solitary; leaf blade not .68. 📌Hapaline

│

├96B.

with an (occasionally absent in Colocasia esculenta); palaeotropical plants

│

┌104A.

Leaf blade pedatisect to radiatisect; female flowers each with several large s .100. 📌Protarum

│

├104B.

Leaf blade entire or ; female flowers without s (except single small ones in Colocasia esculenta)

│

┌105A.

s parietal; s many; leaf blade always entire .103. 📌Colocasia

│

└105B.

; s few; leaf blade entire or .104. 📌Alocasia