ARACEAE
Morphological description
Rhizomatous or tuberous stem, or climbing; herbaceous. Floating herb (Pistia*). Spiny (Lasia, some Cyrtosperma)
Leaves
Leaves alternate or spiral, simple but sometimes deeply lobed and usually hastate, irritating sap. Sometimes single deeply dissected leaf (Amorphophallus); winged petiole (some Pothos); leaves aromatic when crushed (Homalomena); cut surfaces turning orange-brown (Colocasia).
Inflorescence
Inflorescence a fleshy spadix covered by a spathe, individual flowers small sessile, spadix usually consisting of barren top, male flowers in the middle and female flowers at base. Sometimes spathe breaking off in the middle (most Schismatoglottis)
Different from: Lemnaceae: tiny floating herbs. - Taccaceae: inflorescence umbellate, flowers pedicelled. - Zingiberaceae: aromatic, inflorescence not covered by a spathe, individual flowers large.
Distribution: The family widespread, mainly tropical. In Malesia 35 genera,
including: - Aglaonema (Indo-Malesia), shrubby herbs, lowland rain forest; - Alocasia (Indo-Malesia), tuberous herb; - Colocasia (Asia-Pacific), tuberous herb; wet places in forest; - Homalomena (pantropical), rain forest, often along streams; - Pothos (paleotropical), climber, rain forest; - Rhaphidophora (paleotropical), climber, rain forest and monsoon forest.
Notes: Pollination mainly by beetles and flies, fruits of several species eaten by birds. - Edible plants: Alocasia (tubers), Colocasia (tuber, leaves). - Ornamental plants: Aglaonema, Alocasia, Caladium*, Cryptocoryne, Philodendron*, Spathiphyllum.
Literature: C.A. Backer & R.C. Bakhuizen van den Brink, Fl. Java 3 (1968) 100-126; S. J. Mayo, J. Bogner & P.C. Boyce, The genera of Araceae, Roy. Bot. Gard. Kew (1997). - Dr. A. Hay (NSW) is coordinating the revision of the family for Flora Malesiana.
Spot characters (Van Balgooy): All or many taxa: Climbers without hooks or tendrils (p.p.) – Cystoliths – Compact inflorescence – Compound fruits.
In some taxa: Bulbils: Amorphophallus, Remusatia, Schismatoglottis bulbifera – White or yellow sap: Alocasia (p.p.), Colocasia (p.p.), Syngonium – Crushed flowers with a foul smell: some taxa, e.g., Amorphophallus – Crushed leaves with turpentine-like smell: Homalomena (p.p.) - Petioles enlarges at both ends: some taxa, e.g., Homalomena (p.p.) – Peltate leaves: Alocasia (p.p.), Colocasia (p.p.), Homalomena (p.p.), Remusatia – Double marginal vein loops or intramarginal veins: Pedicellarum, Pothos – Bullate leaves: Alocasia (p.p.), Cryptocoryne (p.p.) – Rough leaf surface: Homalomena asperifolia – Plants flowering when leafless: Amorphophallus, Remusatia – Perianth/petals yellow: Cryptocoryne (p.p.) – Stamens bearing appendages or hair tufts: Typhonium.
Illustrations: Fig. 17. Amorphophallus campanulatus (Roxb.) Blume (Araceae). Reproduced from J.J. Ochse & R.C. Bakhuizen van den Brink, Vegetables of the Dutch East Indies (1980) fig. 30. Fig. 18. Colocasia esculenta (L.) Schott (Araceae). Reproduced from M.R. Henderson, Malayan wildflowers, Monocotyledons (1954, repr. 1974) 223. With kind permission of the Malaysian Nature Society. Fig. 19. Pothos versteegii Engl. (Araceae). Reproduced from Blumea 40 (1995) 410. Fig. 20. Rhaphidophora korthalsii Schott (Araceae). Reproduced from M.R. Henderson, Malayan wildflowers, Monocotyledons (1954, repr. 1974) 239. With kind permission of the Malaysian Nature Society. 39.
Image in PhytoImages for Araceae