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Comparative studies of natural groups of organisms
Tassel
Leaf
FOR ONLINE READING ONLY
Brace root or prop root
Styles
Silk Node
Stalk
Roots
Figure 3.30: Structure of a monocot plant showing root and shoot systems
Distinctive features of class have a strip of cambium, which gives
Dicotyledoneae rise to secondary growth.
Members of the class Dicotyledoneae (c) The primary root system in dicots is
(Figure 3.31) have the following features persistent and becomes thick tap root
that make them differ from those of class which develops lateral roots.
Monocotyledoneae. (d) Their seed embryo has two cotyledons.
(a) Dicot leaves have net-like or reticulate (e) Floral parts of dicots are normally
venation with the dorsal and ventral tetramerous or pentamerous (in four or
surfaces of their leaf blade being five or multiples of four or five).
distinct. (f) Pollen grains in dicots mostly have
(b) Their stems have vascular bundles, three apertures.
which appear in a ring form. The
vascular bundles are open, that is, they
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