cycad

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Related to Cycadales: Coniferales

cycad

(sī′kad″, kăd) [L. Cycas, a genus name]
A variety of palmlike evergreen plants, including Cycas revoluta and C. circinalis, from which cycasin has been isolated.

cycad

any tropical or subtropical GYMNOSPERM of the order Cycadales. Cycads date from the MESOZOIC PERIOD. Present-day forms grow to 20 m in height and have a crown of fern-like leaves. They live for up to a thousand years.

cycad

a member of the plant genus of cycas, dioecious, non-flowering woody plants (gymnosperms) which produce seeds in a woody cone consisting of exposed seed leaves (sporophylls), not enclosed in an ovary. The leaves are usually in a rosette at the top of the stem, which may be subterranean. Include Bowenia, Cycas, Dioon, Encephalartos, Lepidozamia, Macrozamia, Zamia spp.

cycad glycoside
group of glycosides including cycasin, macrozamin, found in cycad plants; oxidized in vivo to release toxin methylazoxymethanol (MAM).
References in periodicals archive ?
Zamia, el genero del orden Cycadales con la mayor diversidad morfologica, cariologica y ecologica (Sabato, 1990; Norstog & Nicholls, 1997), consta de cerca de 55 especies principalmente concentradas en el Neotropico.
Las plantas del orden Cycadales producen dos tipos especificos de metabolitos secundarios: los azoxyglicosidos (e.
La acumulacion de cicasina y macrozamina a partir de Cycadales no es, sin embargo, exclusiva en Eumaeus, ya que se presenta tambien en polillas geometridas en Sur Africa (Donaldson, 1991, Donaldson & De Wet Bosenberg, 1995 a, b; Donaldson et al.
Desde el punto de vista coevolutivo, esta relacion no parece responder a un evento de cladogenesis paralela; por el contrario, la notable antiguedad de las Cycadales con respecto a los lepidopteros (los cuales datan de no antes del Cretaceo inferior; cf.
Muchas especies del orden Cycadales son consideradas en peligro de extincion y por lo tanto han sido incluidas en los listados de CITES.
taxonomic categories currently recognized in the Cycadales is in need of
centripetal xylem of the Cycadales is derived from that of the
it appears in the Medullosales, Corystospermales, and Cycadales.
medullary bundles in either the Medullosales or the Cycadales.
In Cycadales, the medullary bundle character has not been
cortical bundles in the stems of some extant Cycadales (Stevenson,
petrificado de Cycadales, Provincia de Rio Negro, Argentina.