Araceae

Arum family Temporal range: 70–0 Ma PreЄ Є O S D C P T J K Pg N Late Cretaceous[1] - Recent
Flower of Xanthosoma roseum
Scientific classification
Kingdom:	Plantae
clade:	Angiosperms
clade:	Monocots
Order:	Alismatales
Family:	Araceae Juss.
Genera
See text.

Peace Lily (Spathiphyllum cochlearispathum) clearly showing the characteristic spadix and spathe.

Araceae are a family of monocotyledonous flowering plants in which flowers are borne on a type of inflorescence called a spadix. The spadix is usually accompanied by, and sometimes partially enclosed in, a spathe or leaf-like bract. Also known as the Arum family, members are often colloquially known as aroid. This family of 107 genera and over 3700 species is most diverse in the New World tropics, although also distributed in the Old World tropics and north temperate regions.

Notable aroid genera and species

Anthurium and Zantedeschia are two well-known members of this family, as are Colocasia esculenta (taro) and Xanthosoma roseum (Elephant ear or ‘ape). Among the largest inflorescence in the world is that of the arum Amorphophallus titanum (Titan arum). The family includes many ornamental plants: Dieffenbachia, Aglaonema, Caladium, Nephthytis, and Epipremnum, to name a few. In the genus Cryptocoryne are many popular aquarium plants. Both Taro and Monstera deliciosa provide food value (the fruit of Monstera deliciosa called "Mexican breadfruit"). Philodendron is an important plant in the ecosystems of the rainforests and is often used in home and interior decorating. Symplocarpus foetidus (skunk cabbage) is a common North American species. An interesting peculiarity is that this family includes the largest unbranched inflorescence, that of the titan arum, often erroneously called the "largest flower" and the smallest flowering plant and smallest fruit, found in the duckweed, Wolffia. Recent genetic research by the Angiosperm Phylogeny Group has shown that the duckweeds, previously treated in a separate family Lemnaceae, also belong in the Araceae family.

The Cuckoo-pint or Lords and Ladies (Arum maculatum) is a common arum in British woodlands

Description

Species in Araceae are often rhizomatous or tuberous and are often found to contain calcium oxalate crystals or raphides. The leaves can vary considerably from species to species. The inflorescence is composed of a spadix, which is almost always surrounded by a modified leaf called a spathe.In monoecious 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 towards the top. In aroids with perfect flowers the stigma is no longer receptive when the pollen is released, thus preventing self-fertilization. There are also some dioecious species.

Many plants in this family are thermogenic (heat-producing). Their flowers can reach up to 45 degrees Celsius even when the surrounding air temperature is much lower. One reason for this unusually high temperature is to attract insects (usually beetles) to pollinate the plant, rewarding the beetles with heat energy. Another reason is to prevent tissue damage in cold regions. Some examples of thermogenic Araceae are: Symplocarpus foetidus (eastern skunk cabbage), Amorphophallus titanum (Titan Arum), Amorphophallus paeoniifolius (elephant foot yam), Helicodiceros muscivorus (dead horse arum lily) and Sauromatum venosum (voodoo lily). Species such as Titan Arum and the dead horse arum give off a very pungent smell, often resembling a rotten animal. This is to attract flies to pollinate the plant. The heat produced by the plant helps to convey the scent further.

History

One of the earliest observations of species in Araceae was conducted by Theophrastus in his work Enquiry into Plants. It wasn't until the 16th century that Araceae was recognized as a distinct group of plants. In 1789 Antoine Laurent de Jussieu classified all climbing aroids as Pothos and all terrestrial aroids as either Arum or Dracontium in his book Families des Plantes. It wasn't until Heinrich Wilhelm Schott published Genera Aroidearum in 1858 and Prodromus Systematis Aroidearum in 1860 that major classification progress was made in the family. At the time of writing these books Schott was only aware of approximately 900 species that he subsequently classified into 12 tribes. These 12 tribes grew to become the primary framework from which all subsequent classification was based.

The largest collection of living Araceae is maintained at Missouri Botanical Gardens.^[2] Another large collection of living Araceae can be found at Munich Botanical Garden, thanks to the efforts of the researcher and aroid authority Josef Bogner.

Toxicity

Within the Aracae, genera such as Alocasia, Arisaema, Caladium, Colocasia, Dieffenbachia, Philodendron contain calcium oxalate crystals in the form of raphides. When consumed, these may cause edema, vesicle formation and dysphagia accompanied by painful stinging and burning to the mouth and throat, the symptoms occurring for up to two weeks.^[3]

List of genera

Subfamily Aroideae

Arisaema triphyllum

Calla palustris

Cyrtosperma

Wolffia arrhiza

Anthurium

Spathiphyllum

Orontium aquaticum

Zamioculcas zamiifolia

• Aglaodorum Schott
• Aglaonema Schott
• Alocasia (Schott) G. Don
• Amorphophallus Blume ex Decne.
• Ambrosina Bassi
• Anchomanes Schott
• Anubias Schott
• Aridarum Ridl.
• Ariopsis Nimmo
• Arisaema Mart.
• Arisarum Mill.
• Arophyton Jum.
• Arum L.
• Asterostigma Fisch. & C. A. Mey.
• Biarum Schott
• Bognera Mayo & Nicolson
• Bucephalandra Schott
• Caladium Vent.
• Callopsis Engl.
• Carlephyton Jum.
• Cercestis Schott
• Chlorospatha Engl.
• Colletogyne Buchet
• Colocasia Schott
• Cryptocoryne Fisch. ex Wydler
• Culcasia P. Beauv.
• Dieffenbachia Schott
• Dracunculus Mill.
• Eminium (Blume) Schott
• Filarum Nicolson
• Furtadoa M. Hotta
• Gearum N. E. Br.
• Gorgonidium Schott
• Hapaline Schott
• Helicodiceros Schott
• Heteroaridarum M. Hotta
• Homalomena Schott
• Hottarum Bogner & Nicolson
• Jasarum G. S. Bunting
• Lagenandra Dalzell
• Mangonia Schott
• Montrichardia Crueg.
• Nephthytis Schott
• Peltandra Raf.
• Philodendron Schott
• Phymatarum M. Hotta
• Pinellia Ten.
• Piptospatha N. E. Br.
• Pistia L.
• Protarum Engl.
• Pseudodracontium N. E. Br.
• Pseudohydrosme Engl.
• Remusatia Schott
• Sauromatum Schott
• Scaphispatha Brongn. ex Schott
• Schismatoglottis Zoll. & Moritzi
• Spathantheum Schott
• Spathicarpa Hook.
• Steudnera K. Koch
• Stylochaeton Lepr.
• Synandrospadix Engl.
• Syngonium Schott
• Taccarum Brongn. ex Schott
• Theriophonum Blume
• Typhonium Schott
• Typhonodorum Schott
• Ulearum Engl.
• Xanthosoma Schott
• Zantedeschia Spreng.
• Zomicarpa Schott
• Zomicarpella N. E. Br.

Subfamily Calloideae

• Calla L.

Subfamily Gymnostachydoideae

• Gymnostachys R. Br.

Subfamily Lasioideae

• Anaphyllopsis A. Hay
• Anaphyllum Schott
• Cyrtosperma Griff.
• Dracontioides Engl.
• Dracontium L.
• Lasia Lour.
• Lasimorpha Schott
• Podolasia N. E. Br.
• Pycnospatha Thorel ex Gagnep.
• Urospatha Schott

Subfamily Lemnaoideae

• Landoltia
• Lemna
• Spirodela
• Wolffia
• Wolffiella

Subfamily Monsteroideae

• Alloschemone Schott
• Amydrium Schott
• Anadendrum Schott
• Epipremnum Schott
• Heteropsis Kunth
• Holochlamys Engl.
• Monstera Adans.
• Rhaphidophora Hassk.
• Rhodospatha Poepp.
• Scindapsus Schott
• Spathiphyllum Schott
• Stenospermation Schott

Subfamily Orontioideae

• Lysichiton Schott
• Orontium L.
• Symplocarpus Salisb. ex W. P. C. Barton

Subfamily Pothoideae

• Anthurium Schott
• Pedicellarum M. Hotta
• Pothoidium Schott
• Pothos L.

Subfamily Zamioculcadoideae

• Gonatopus Hook. f. ex Engl.
• Zamioculcas Schott

Subfamily incertae sedis

• † Petrocardium Herrera et al (Paleocene, Cerrejón Formation, Colombia) ^[4]

See also

List of foliage plant diseases (Araceae)

Notes

1. ^ Bogner, Josef; Johnson, Kirk R.; Kvacek, Zlatko; Upchurch, Garland R. Jr (2007). "New fossil leaves of Araceae from the Late Cretaceous and Paleogene of western North America". Zitteliana 47: 133–147. 
2. ^ . "The resources which have been built up for aroid research at the Missouri Botanical Garden include one of the largest living collections of aroids and the largest collection of herbarium specimens of neotropical aroids. The living and dried collections include a large percentage of Croat's more than 80,000 personal collections". (Croat, Thomas B (1998). "History and Current Status of Systematic Research with Araceae". Aroideana 21. )
3. ^ Outbreak of Food-borne Illness Associated with Plant Material Containing Raphides. Informa Healthcare.
4. ^ Herrera, F.A.; Jaramillo, C.A.; Dilcher, D.L.; Wing, S.L.; Gómez-N, C. (2007). "Fossil Araceae from a Paleocene neotropical rainforest in Colombia". American Journal of Botany 95 (12): 1569–1583. doi:10.3732/ajb.0800172. 

References

• Bown, Deni (2000). Aroids: Plants of the Arum Family [ILLUSTRATED]. Timber Press. ISBN 0-88192-485-7
• Croat, Thomas B (1998). "History and Current Status of Systematic Research with Araceae". Aroideana 21.  on line
• Grayum, Michael H (1990). "Evolution and Phylogeny of the Araceae". Annals of the Missouri Botanical Garden 77 (4). 
• 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. 

External links

• CATE-Araceae (and Network Araceae)
• An interactive key to the genera of Araceae
• International Aroid Society
• list of publications (March 2008) for Dr. h.c. Josef Bogner