Monocot, Dicot, Eudicot?

Question

Can anyone give me the meanings of these words and the differences between them.

writing botany to describe different roots

Answer 1

Monocot and dicot you already got explained.

Eudicot is actually  same as dicot - and it is not the same. It is quite new name for " modern" dicots. The plants that are not eudicots could be called paleodicots referring to their more primitive origin. eudicots and paleodicots have very little differences: main differences are in structure of pollen.

To be exact, angiosperms (flowering plants) are divided to eight groups:

Amborella,Nymphaeales,Austrobaileyales... Ceratophyllum,magnoliids (paleodicots),eudicots and monocots.

This is quite complicated, I know, but angiosperm phylogeny has been under major constructions in last 10 years.

check the tree of life:

http://www.tolweb.org/Angiosperms

But about major differences between theree groups you mentioned:

monocots:

- single cotyledon

-vascular bundles irregularly distributed in cross section of the stem

-parallel veins in the leaves

-flower parts in multiples of three.

- lack of true secondary growth

- in root vascular bundles arranged in a ring

- Roots are adventitious  (=the radicle aborts  and new roots arise adventitiously from nodes in the stem)

dicots:

- two cotyledons  

- Flower parts in multiples of four or five  

- Major leaf veins reticulated  

-Stem vascular bundles in a ring  

-in root vascular bundles arranged in middle of the plant

-Roots develop from radicle  (=In most dicots  the root develops from the lower end of the embryo, from a region known as the radicle. The radicle gives rise to an apical meristem which continues to produce root tissue for much of the plant's life.)

-Secondary growth often present  

eudicot have same characteristics as dicots.

Answer 2

the first two are pretty easy

The name monocotyledons is derived from the traditional botanical name Monocotyledones, which derives from the fact that most members of this group have one cotyledon, or embryonic leaf, in their seeds. This as opposed to the traditional Dicotyledones, which typically have two cotyledons the otherone I dont know much about