The Arecidae
Family Overview - Arales

Araceae  - the Arum Family

Diversity:  Perennial herbs, often terrestrial or climbing via adventitious roots, rarely floating aquatic (Pistia).  Many taxa have extended their tropical range into temperate offices and homes as foliage ornamentals (Philodendron, Dieffenbachia, Monstera), 'floral' ornamentals (Anthurium) and Colocasia esculenta is an important food plant of the tropics (taro, poi).  The family includes about 105 genera and more than 3,300 species.

Distribution:  Worldwide in tropical and subtropical areas with some taxa (less than 10%) extending into temperate habitats. We have 8 genera and 9 species (2 species of Arisaema) in Texas.

Floral structure:

Significant features:  Variable vegetatively, although presence of toxic calcium oxalate crystals (raphides) is common, and the flowers, highly reduced, are of little value for identification.  The unusual inflorescence provides a strong key character in the field.  Similar to the Asteraceae, small flowers of the Araceae, either perfect or unisexual, are aggregated on a common receptacle.  This structure, known as a spadix, is usually elongate with the flowers attached - or embedded - along its axis.  The spadix is usually subtended by a highly modified bract, knows as the spathe.  This combination - spadix and spathe - serves as an excellent marker for the family.

Arismaea triphyllum - 'jack in the pulpit'

plant in flower
'jack in the pulpit' (spadix enclosed by distinctive spathe)


Plant in flower
inflorescence (spadix) with spathe
spadix with spathe removed

Pistia - transition to the Lemnaceae?

Pistia stratiotes - plants in habitat - Marco Island, Florida 
Pistia stratiotes - plant and inflorescence (right) - from the University of Hawaii

More information on the Araceae
Amorphophallus titanum

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