Family Araceae
Habit and leaf form. Shrubs, or herbs, or ‘arborescent’; laticiferous, or with coloured juice, or non-laticiferous and without coloured juice. ‘Normal’ plants. Perennial; with a basal aggregation of leaves, or with neither basal nor terminal aggregations of leaves; often cormous, or rhizomatous, or tuberous. Self supporting, or epiphytic, or climbing (some very large); when climbing stem twiners, or root climbers, or scrambling. Hydrophytic, or helophytic, or mesophytic; when hydrophytic rooted, or free floating (Pistia). Leaves when hydrophytic, submerged, or emergent. Heterophyllous (often entire/lobed compound), or not heterophyllous. Leaves small to very large; alternate; spiral, or distichous; petiolate (appearing conventionally ‘petiolate’ when the sheath shed), or sessile (Pistia only); sheathing (the sheath membranous, sometimes deciduous). Leaf sheaths with free margins. Leaves with ‘normal’ orientation (Acorus being excluded); simple, or compound. Lamina pinnately veined, or palmately veined, or parallel-veined; cross-venulate, or without cross-venules; often cordate, or hastate, or sagittate. Leaves ligulate, or eligulate. Axillary scales present, or absent. Leaves without a persistent basal meristem; often becoming compound by necrosis. General anatomy. Plants with laticifers (articulated, branched or not), or without laticifers (e.g. some Pothoideae, Pistia). Plants without silica bodies. Accumulated starch other than exclusively ‘pteridophyte type’. Leaf anatomy. Stomata present (usually randomly orientated); paracytic, or tetracytic, or cyclocytic, or anomocytic (etc.). Guard-cells not ‘grass type’. Lamina dorsiventral. The mesophyll without etherial oil cells; containing mucilage cells (with raphides), or not containing mucilage cells; containing calcium oxalate crystals. The mesophyll crystals raphides and druses. Minor leaf veins without phloem transfer cells (5 genera). Vessels absent. Stem anatomy. Secondary thickening absent. Xylem without vessels. Sieve-tube plastids P-type; type II. Root anatomy. Roots with velamen (rarely), or without velamen. Root xylem with vessels; vessel end-walls scalariform. Reproductive type, pollination. Plants hermaphrodite, or monoecious (then the males above), or andromonoecious, or gynomonoecious, or gynodioecious, or polygamomonoecious. Pollination anemophilous (rarely), or entomophilous; mechanism conspicuously specialized (involving protogyny, combined with the trapping of insects in the spathe, and their subsequent release), or unspecialized. Inflorescence, floral, fruit and seed morphology. Flowers aggregated in ‘inflorescences’; in spikes (very rarely shortly pedicellate — Pedicellarum). The ultimate inflorescence unit seemingly racemose. Inflorescences scapiflorous (usually, more or less), or not scapiflorous; consisting of specialised spikes (‘spadices’) with spirals or rarely whorls of flowers, variously pedunculate, sometimes tipped by a naked ‘appendix’; usually conspicuously, often spectacularly spatheate, or espatheate (in that there may be no true spathe in Gymnostachys, Orontium). Flowers ebracteate; ebracteolate; small (numerous); (these or the spadix) often fragrant, or malodorous; regular to very irregular; when irregular, asymmetric; 1–3 merous; cyclic. Perigone tube present (Spathiphyllum), or absent (usually). Perianth of ‘tepals’, or absent; 0, or 4, or 6, or 8 (rarely 12); free (usually), or joined; when present, 2 whorled (3+3 or 2+2); isomerous; when present, sepaloid; similar in the two whorls (small, inconspicuous, often thick). Androecium 1 (e.g. Cryptocoryne), or 4, or 6, or 8(–12). Androecial members free of the perianth; free of one another, or coherent; 1 whorled, or 2 whorled (commonly 3+3 or 2+2). Androecium exclusively of fertile stamens. Stamens 1–4, or 6, or 8–12; reduced in number relative to the adjacent perianth to isomerous with the perianth to triplostemonous. Anthers basifixed; non-versatile; dehiscing via pores, or dehiscing via short slits, or dehiscing via longitudinal slits, or dehiscing transversely; extrorse; bisporangiate, or tetrasporangiate. Endothecium developing fibrous thickenings. The endothecial thickenings spiral. Anther epidermis persistent. Microsporogenesis successive. The initial microspore tetrads tetrahedral, or isobilateral, or decussate. Anther wall of the ‘monocot’ type. Tapetum amoeboid. Pollen shed in aggregates (occasionally), or shed as single grains; when in aggregates, in tetrads (e.g. Caladium, Xanthosma). Pollen grains aperturate, or nonaperturate; 1 aperturate, or 2–9 aperturate (?); when aperturate, sulcate, or sulculate, or foraminate; 2-celled (10 genera), or 3-celled (7 genera). Gynoecium (1–)3(–8) carpelled. The pistil 1 celled, or (1–)3(–8) celled. Gynoecium monomerous, or syncarpous; of one carpel, or synstylovarious to eu-syncarpous (?); superior. Carpel non-stylate; apically stigmatic; (when monomerous,) 1–5 ovuled (?). Placentation apical, or marginal, or basal (?). Ovary when syncarpous, (1–)3(–8) locular. The ‘odd’ carpel when trilocular, posterior. Gynoecium shortly non-stylate, or stylate. Styles 1; apical. Stigmas wet type, or dry type; non-papillate; Group II type. Placentation when syncarpous/unilocular, parietal, or basal, or apical; when plurilocular, axile. Ovules in the single cavity when unilocular, 1–15(–50) (?); 1–15(–100) per locule (?); pendulous, or horizontal, or ascending; orthotropous, or hemianatropous (rarely), or anatropous; bitegmic; tenuinucellate (e.g. Pistia), or crassinucellate (weakly), or pseudocrassinucellate. Embryo-sac development Polygonum-type. Polar nuclei fusing prior to fertilization. Antipodal cells formed; initially 3; proliferating (to a limited extent, e.g. Lysichiton), or not proliferating (usually); ephemeral (usually), or persistent. Synergids pear-shaped. Hypostase present, or absent. Endosperm formation helobial (though ostensibly cellular, and long described as such). Endosperm haustoria present; chalazal. Embryogeny caryophyllad (usually), or onagrad (e.g. Pistia). Fruit fleshy (usually), or non-fleshy; an aggregate, or not an aggregate. The fruiting carpel when monomerous, indehiscent; drupaceous, or baccate, or nucular. Fruit indehiscent (usually), or dehiscent; a capsule to capsular-indehiscent (occasionally), or a berry, or a drupe, or a nut (occasionally). Capsules when present, splitting irregularly. Gynoecia of adjoining flowers combining to form a multiple fruit (usually), or not forming a multiple fruit. The multiple fruits coalescing (sometimes), or not coalescing. Dispersal unit the fruit, or the inflorescence (the spadix sometimes forming a syncarp). Seeds endospermic, or non-endospermic. Endosperm when present, oily (and starchy). Perisperm absent. Seeds with starch. Cotyledons 1. Embryo chlorophyllous (6/6), or achlorophyllous (Arisaema amurense); straight (linear). Testa without phytomelan; membranous, leathery or crustaceous, but not black?. Seedling. Hypocotyl internode present (commonly, short to fairly long, sometimes developing into a storage organ, e.g. Arisaema), or absent (e.g. Pistia). Seedling collar not conspicuous. Cotyledon hyperphyll compact; assimilatory, or non-assimilatory (functioning entirely as a haustorium, or as a storage cum assimilatory organ, or combining all these functions). Coleoptile absent. Seedling when the seed non-endospermic, non-macropodous. Seedling cataphylls present or absent. First leaf dorsiventral. Primary root ephemeral (and sometimes absent alogether). Physiology, biochemistry. Cyanogenic, or not cyanogenic. Cynogenic constituents tyrosine-derived. Alkaloids present (commonly), or absent. Proanthocyanidins present (commonly, sometimes very abundantly), or absent; when present, cyanidin. Flavonols present, or absent; when present, kaempferol, or quercetin, or kaempferol and quercetin. Ellagic acid absent. Saponins/sapogenins present (in some genera), or absent (?). C3. C3 physiology recorded directly in Colocasia, Pistia, Pothos. Anatomy non-C4 type (Alocasia, Colocasia, Peltandra, Pistia, Pothos). Geography, cytology. Sub-tropical, or tropical, or temperate (relatively few). Widespread. Taxonomy. Subclass Monocotyledonae. Superorder Ariflorae; Arales. APG (1998) Monocot; non-commelinoid. APG 3 (2009) Order: Alismatales. Species 2000. Genera 106; Aglaodorum, Aglaonema, Alloschemone, Alocasia, Ambrosina, Amorphophallus, Amydrium, Anadendrum, Anaphyllopsis, Anaphyllum, Anchomanes, Anthurium, Anubias, Aridarum, Ariopsis, Arisaema, Arisarum, Arophyton, Arum, Asterostigma, Biarum, Bognera, Bucephalandra, Caladium, Calla, Callopsis, Carlephyton, Cercestis, Chlorospatha, Colletogyne, Colocasia, Cryptocoryne, Culcasia, Cyrtosperma, Dieffenbachia, Dracontioides, Dracontium, Dracunculus, Eminium, Epipremnum, Filarum, Furtodoa, Gearum, Gonatanthus, Gonatopus, Gorgonidium, Gymnostachys, Hapaline, Helicodiceros, Heteroaridarum, Heteropsis, Holochlamys, Homalomena, Hottarum, Jasarum, Lagenandra, Lasia, Lasimorpha, Lysichiton, Mangonia, Monstera, Montrichardia, Nephthytis, Orontium, Pedicellarum, Peltandra, Philodendron, Phymatarum, Pinellia, Piptospatha, Pistia, Podolasia, Pothoidium, Pothos, Protarum, Pseudodracontium, Pseudohydrosme, Pycnospatha, Remusatia, Raphidophora, Rhodospatha, Sauromatum, Scaphispatha, Schismatoglottis, Scindapsus, Spathantheum, Spathicarpa, Spathiphyllum, Stenospermation, Steudnera, Stylochaeton, Symplocarpus, Synandrospadix, Syngonium, Taccarum, Theriophonum, Typhonium, Typhonodorum, Ulearum, Urospatha, Urospathella, Xanthosoma, Zamiculcas, Zantedeschia, Zomicarpa, Zomicarpella. Economic uses, etc. The family furnishes numerous horticultural ornamentals, especially for indoors, and a few are grown for food — e.g. Colocasia for taro, Monstera for its ‘fruits’ (‘Mexican breadfruit’). |
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