Araceae

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Aroid Family

Philodendron brevispathum Schott, an understory herb in the Araceae. Note the finely parallel tertiary veins and the spadix and spathe inflorescence. Una hierba del sotobosque. Note las venas finas paralelas, y la inflorescencia de espádice y espata.


Description: A large and important family of herbaceous plants in the Neotropics, with many climbers and hemiepiphytes. The leaves are alternate, simple to palmately compound, and usually entire. Unlike most monocots, aroids can have reticulate venation (i.e., the veins form a network). Many species have caustic and/or foul-smelling latex. The inflorescence is unmistakable: a spadix (a stalk of many tiny, closely appressed flowers) subtended by a spathe (a single large, sheathing bract). Vegetatively, the family can usually be identified by its more or less succulent leaves and petioles, and the glossy sheen of its leaves. A good key to the aroid genera of La Selva Biological Station can be found in the OTS 96-9 course book, page 95 (available in the La Selva library).

As a former Carleton College tropical ecology class discovered (see the 1998 course book, also in the La Selva library), water held in the leaf axils of the aroid Dieffenbachia longispatha is a favorite brood site for the “blue jeans frog” (Dendrobates pumilio).

Economic uses: Many aroids are planted as ornamentals. Monstera deliciosa, a hemiepiphyte, is cultivated for its fruit in Central and South America. The aquatic aroid Colocasia esculenta var. antiquorum, known as taro, was a traditional staple throughout the Pacific islands and is now grown in the Neotropics as well. Most Araceae are toxic, though, due to high concentrations of calcium oxalate crystals and other secondary compounds in their tissues.


Descripción: Una familia diversa e importante de plantas herbáceas en la zona neotropical. Contiene plantas trepadoras y hemiepífitas. Las hojas son alternas, simples a palmaticompuestas, y usualmente enteras. A diferencia de otras monocotiledóneas, las Araceas tienen venas que forman una red (en lugar de seguir paralelas). Muchas especies tienen savia cáustica o fétida. La inflorescencia es inconfundible: un espádice (una espiga con muchas flores pequeñitas y hundidas) y una espata (una bráctea grande que envuelve la base de la espiga). Estérilmente, se reconocen las Araceas por las hojas y pecíolos más o menos suculentos, y el brillo lustroso de las hojas. Hay una buena clave para los géneros de Araceas en la Estación Biológica La Selva en el libro del curso OET 96-9, p. 95 (disponible en la biblioteca de La Selva).

Un curso de ecología tropical de Carleton College descubrió que la rana “bluejeans” (Dendrobates pumilio) frecuentemente usa las cuencas de agua en las axilas de las hojas de Dieffenbachia longispatha para poner sus huevos.

Usos económicos: Muchas especies de Araceas se usan como plantas ornamentales. La hemiepífita Monstera deliciosa se cultiva en Centroamérica y Suramérica por sus deliciosos frutos. Colocasia esculenta, (malanga o ñampi), era una comida indispensable para los indios del Pacífica Sur, y ahora se cultiva frecuentemente en la zona neotropical. Sin embargo, la mayoría de las Araceas son venenosos, debido a altas concentraciones de oxalatos de calcio y otros compuestos.


Genera/species at La Selva: 16/103: Alocasia (3), Anthurium (25), Caladium (1), Colocasia (1), Dieffenbachia (7), Dracontium (1), Heteropsis (1), Homalomena (1), Monstera (10), Philodendron (32), Rhodopsatha (2), Spathiphyllum (5), Stenospermation (2), Syngonium (7), Urospatha (1), Xanthosoma (4).


FIELD MARKS – Inflorescence consisting of a fleshy spike (spadix) covered in minute flowers and a showy leaf-like spathe. Mostly climbers and epiphytes with large leaves or with leaves plastered to the trunk of a host tree.


Anthurium inflorescence consisting of a fleshy spadix containing many tiny flowers and a leaf-like spathe bent away from the spadix.
Spathe and spadix inflorescence distinguishes the Araceae.
Epiphytic Anthurium showing spathe oriented away from the spadix, a characteristic of the genus.
Epiphytic Anthurium with large leaves and distinctive inflorescence.
Inflorescence of Philodendron radiatum illustrating the constriction in the middle of the spathe and swollen base that defines the genus.
Large epiphytic Philodendron.
Monstera climber showing two very different types of leaves.
Monstera species are climbers that begin life on the ground and climb up tree trunks to get access to the canopy. Many species grow with lower leaves plastered against the trunk of the host tree, only to produce larger more elaborate leaves of a completely different shape upon reaching the canopy.
“Moostera deliciosa” sculpture in San Jose’s Parque National.
Monstera tenuis is an epiphytic climber with “dinner plate” leaves that cling to the trunks of host trees. Once they reach a certain height, large dissected leaves are produced.
Epiphytic climbers with large leaves and pinnate venation are likely to be members of the Araceae.


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