TheAraceae are afamily ofmonocotyledonousflowering plants in whichflowers are borne on a type ofinflorescence called aspadix. The spadix is usually accompanied by, and sometimes partially enclosed in, aspathe (or leaf-likebract). Also known as thearum family, members are often colloquially known asaroids. This family of 114genera and about 3,750 known species[3] is most diverse in theNew World tropics, although also distributed in theOld World tropics and northerntemperate regions.
Within the Araceae, species are oftenrhizomatous ortuberous; many areepiphytic, creepinglianas orvining plants, and theleaves and tissues of the entire plant nearly always contains irritatingcalcium oxalate crystals orraphides, in varying degrees.[4][5] The foliage can vary considerably from species to species. The majority of species produce aninflorescence consisting of a spadix (which some compare to acorn cob, in appearance), which is nearly always surrounded by a modified leaf bract called aspathe.[6] Inmonoecious aroids, possessing separate male and female flowers (but with both flowers present on one plant), the spadix is usually organized with female flowers towards the bottom and male flowers at the top. In aroids withperfect flowers, thestigma is no longer receptive when thepollen is released, thus preventing self-fertilization. Some species aredioecious.[7]
Many plants in this family arethermogenic (heat-producing).[8] Their flowers can reach up to 45 °C, even if the surrounding air temperature is much lower. One reason for this unusually high temperature is to attract insects (usuallybeetles) to pollinate the plant, rewarding the beetles with heat energy, in addition to preventing tissue damage in colder regions. Some examples of thermogenic aroids areSymplocarpus foetidus (eastern skunk-cabbage),Amorphophallus titanum (titan arum),Amorphophallus paeoniifolius (elephant-foot yam),Helicodiceros muscivorus (dead-horse arum lily), andSauromatum venosum (voodoo lily). Some species, such asA.titanum andH.muscivorus, give off a very pungent smell akin to rotten meat, which serves to attract flies for pollination. The heat produced by the plant helps to convey the scent further.
Within the Araceae family, the majority of species produce calcium oxalate crystals in the form ofraphides. While it is possible to consume the cooked foliage of certain genera, such asAlocasia,Colocasia, andXanthosoma, as well as the ripened fruits ofMonstera deliciosa, these raphide compounds are irritating (and even dangerous) for many animals, including humans. Consumption of raw aroid vegetation may causeedema,vesicle formation ordysphagia, accompanied by a painful stinging and burning in the mouth and throat, with symptoms occurring for up to two weeks, depending on amount consumed. In smaller amounts, patients report feeling a mild to extreme sensation of sand or glass in the esophagus and mouth, lasting up to 48 hours.[9] Additionally, in heavier instances of ingestion,anaphylactic shock could cause swelling of the throat, restricting breathing. The genusDieffenbachia is famously known as "dumb-cane" for this reason; however, given the presence of irritating compounds across the family, this nickname may be applied to virtually any genera within the Araceae.
One of the earliest observations of species in the Araceae was conducted byTheophrastus in his workEnquiry into Plants.[11] The Araceae were not recognized as a distinct group of plants until the 16th century. In 1789,Antoine Laurent de Jussieu classified all climbing aroids asPothos and all terrestrial aroids as eitherArum orDracontium in his bookFamilles des Plantes.[citation needed]
The first major system of classification for the family was produced byHeinrich Wilhelm Schott, who publishedGenera Aroidearum in 1858 andProdromus Systematis Aroidearum in 1860. Schott's system was based on floral characteristics, and used a narrow conception of a genus.Adolf Engler produced a classification in 1876, which was steadily refined up to 1920. His system is significantly different from Schott's, being based more on vegetative characters and anatomy. The two systems were to some extent rivals, with Engler's having more adherents before the advent ofmolecular phylogenetics brought new approaches.[12]
A comprehensive taxonomy of Araceae was published by Mayo et al. in 1997.[13]
Modern studies based on gene sequences show the Araceae (including theLemnoideae, duckweeds) to bemonophyletic, and the first diverging group within theAlismatales.[14] TheAPG III system of 2009 recognizes the family, including the genera formerly segregated in the Lemnaceae.[15] The sinking of the Lemnaceae into the Araceae was not immediately universally accepted. For example, the 2010New Flora of the British Isles used aparaphyletic Araceae and a separate Lemnaceae.[16] HoweverLemna and its allies were incorporated in Araceae in the 2019 edition.[17]: 872 A comprehensivegenomic study ofSpirodela polyrhiza was published in February 2014.[18]
143 genera are accepted within the Araceae.[19]Anthurium,Epipremnum,Monstera,Philodendron andZantedeschia are some of the most well-known genera of the family, as are theColocasia (taro,arbi) andXanthosoma ('elephant-ear', ‘ape), which are both cultivated for human consumption. The largest unbranched inflorescence in the world is that of the arumAmorphophallus titanum (titan arum).[20]
The Araceae includes many ornamental genera of global economic importance:Aglaonema,Alocasia,Anthurium,Caladium,Dieffenbachia,Epipremnum,Homalomena, Monstera,Nephthytis,Rhaphidophora,Scindapsus,Spathiphyllum,Syngonium, andZamioculcas, to name but a few. The aquatic generaAnubias,Bucephalandra andCryptocoryne are highly prized and cultivated aquarium plants; other, recently-described genera, such as theLagenandra of India, are gradually becoming more known in theaquascaping world.[21]Philodendron is an important genus in the ecosystems ofneotropicalrainforests, and is widely used in home and interior decorating.Symplocarpus foetidus (skunk cabbage) is a common eastern North American species. An interesting peculiarity is that this family includes the largest unbranched inflorescence, that of thetitan arum,[20] often erroneously called the "largest flower", and the smallest flowering plant and smallest fruit, in theduckweed,Wolffia.[22]
The family Araceae has one of the oldestfossil record amongangiosperms, with fossil forms first appearing during theEarly Cretaceous epoch.[1][23] Notable fossils from the Early Cretaceous include:Spixiarum kipea,[24] an aroid from the lateAptian of Brazil;[1]Orontiophyllum ferreri, an aroid leaf from the lateAlbian of Spain;[1] andTurolospadix bogneri, an aroid spadix from the late Albian of Spain.[1]
Food plants in the family Araceae includeAmorphophallus paeoniifolius (elephant foot yam),Colocasia esculenta (kochu, taro, dasheen),Xanthosoma (cocoyam, tannia),Typhonium trilobatum andMonstera deliciosa (Mexican breadfruit). While the aroids are little traded, and overlooked by plant breeders to the extent that the Crop Trust calls them "orphan crops", they are widely grown and are important insubsistence agriculture and in local markets. The main food product is thecorm, which is high instarch; leaves and flowers also find culinary use.[25]
^abcdeSender, L.M., Doyle, J.A., Upchurch, J.R. Jr., Villanueva-Amadoz, U. and Diez J.B. 2019. Leaf and inflorescence evidence for near-basal Araceae and an unexpected diversity of other monocots from the late Early Cretaceous of Spain. Journal of Systematic Palaeontology, vol. 17, p. 1093–1126.
^Angiosperm Phylogeny Group (2009), "An update of the Angiosperm Phylogeny Group classification for the orders and families of flowering plants: APG III",Botanical Journal of the Linnean Society,161 (2):105–121,doi:10.1111/j.1095-8339.2009.00996.x,hdl:10654/18083
^Watson, John T.; Jones, Roderick C.; Siston, Alicia M.; Diaz, Pamela S.; Gerber, Susan I.; Crowe, John B.; Satzger, R. Duane (2005). "Outbreak of Food-borne Illness Associated with Plant Material Containing Raphides".Clinical Toxicology.43 (1):17–21.doi:10.1081/CLT-44721.PMID15732442.S2CID388923.
^Grayum, Michael H. (1990), "Evolution and Phylogeny of the Araceae",Annals of the Missouri Botanical Garden,77 (4):628–697,doi:10.2307/2399668,JSTOR2399668
^Mayo, S. J.; Bogner, J.; Boyce, P. C. (1997).The genera of Araceae. London: Royal Botanic Gardens, Kew.ISBN1-900347-22-9.OCLC60140655.
^Nauheimer, L., Metzler, D. and Renner, S.S. 2012. Global history of the ancient monocot family Araceae inferred with models accounting for past continental positions and previous ranges based on fossils. New Phytologist, vol. 195, p. 938-950.
^Coiffard, C., Mohr, B.A.R. and Bernardes de Oliveira, M.E.C. 2013. The Early Cretaceous aroid,Spixiarum kipea gen. et sp. nov., and implications on early dispersal and ecology of basal monocots. Taxon, vol. 62. p. 997-1008.
Bown, Deni (2000). Aroids: Plants of the Arum Family [ILLUSTRATED]. Timber Press.ISBN0-88192-485-7
Croat, Thomas B (1998). "History and Current Status of Systematic Research with Araceae".Aroideana.21.online
Grayum, Michael H (1990). "Evolution and Phylogeny of the Araceae".Annals of the Missouri Botanical Garden.77 (4):628–697.doi:10.2307/2399668.JSTOR2399668.
Keating R C (2004). "Vegetative anatomical data and its relationship to a revised classification of the genera of Araceae".Annals of the Missouri Botanical Garden.91 (3):485–494.JSTOR3298625.
_-_2.jpg)
