1) There are four basic types of stomata among dicotyledons distinguished based on the subsidiary cells surrounding the stomata and their arrangements. 2) The four types are anomocytic (Ranunculaceae), anisocytic (Curciferae), paracytic (Rubiaceae), and diacytic (Caryophyllaceae). 3) Each type is characterized by the orientation and number of subsidiary cells surrounding the guard cells and pore.

1. Anuj Kumar Srivastava
Asst. professor
Kailash Institute of Pharmacy & management, GIDA, Gorakhpur

2. A stoma is a minute epidermal opening with
following characteristics:
 A central
 Two kidney shaped similar cells containing
chloroplasts known as Guard cells and
varying number of subsidiary (epidermal)
cells covering the guard cells.
 A stoma is made up of a pair of identical
guard cells, forming a pore in centre through
which gaseous exchange takes place.


4. 

A)
B)
C)
D)
There are 4 basic types of stomata among the
dicotyledons, these types are distinguished
on the basis of the subsidiary cells
surrounding
the
stomata
&
their
arrangements,
The four types are as the following
Anomocytic type, Ranunculaceae
Anisocytic type, Curciferae
Paracytic type, Rubiceae
Diacytic type, Caryophyllaceae

5. 
The surrounding epidermal cells have no
special arrangement, they are all similar &
there are no subsidiary cells, so all the cells
are normal epidermal cells without any
modification, like to stomata of digitalis, see
the following example pictures.

6. 
The stomata is surrounded by 3 or more
subsidiary cells, one of them is distinctly
smaller that the others like in Hyoscymus
niger, check the following picture.

7. 
Each stoma is surrounded by 2 or more subsidiary
cells, 2 of them have their long axes parallel to the
pore, which means that the axes of the subsidiary
cells are parallel to the axes of the pore like the one
in senna leaves, check the following picture.

8. 
Each stomata is surrounded by 2 subsidiary
cells having their long axes perpendicular to
the pore like in peppermint, Mentha
piper, check the following picture

10. 



Paracytic or Rubiaceous or parallel- celled
stomata: Cocca leaf, senna leaf
Diacytic or caryophyllaceous or cross-celled
stomata : Peppermint, Vasaka
Anisocytic or cruciferous or Unequial celled
stomata: Belladona, Datura
Anomocytic or ranunculaceous or irregular
celled stomata: Digitalis, Lobelia

11. Thank you