Dicotylédone

In general, the dicotylédones present a seedling to two Cotylédon S, which differentiates them from the Monocotylédone S which, in general, present one of them. The Feuille S have Nervure S réticulées. The Fleur S share with the establishment of the sheets a symmetry of order 4 or 5. The typical flower presents 4 verticils (Sépale S, Pétale S, cheesecloth S and Carpelle S). In the majority of the species, the root is of type swivelling.

It is at the dicotylédones that one observes, on the level of the stems, the presence of Cambium allowing the secondary formation of wood towards the interior and Liber towards outside.

The dicotylédones are known under the scientific names: Dicotyledoneae , Dicotyledones , Magnoliopsida , etc, depend on adopted classification.

In the traditional classification of Cronquist (1981) the dicotylédones are divided into six subclass S:

The groups of the Rosidae and the Asteridae are groups of recent appearance having evolved to sometimes complex floral structures as the capitulates of Astéracées.

In the phylogenetic classification APG II (2003), the dicotylédones are regarded as paraphyletic, the clade including/understanding them all (Angiospermes) also including the monocotylédones.

At the true dicotylédones ''' ''', the grains of Pollen generally have 3 apertures (zones of weakness allowing the passage of the pollen tube). The primitive angiospermes, classically parts of dicotylédones, had grains of pollen with only one aperture, like the Monocotylédone S.

References

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