Npc stands for number position character classification for pollen apertures. outer surface of pollen layer .

2. NPC system
• Number position and character of aperture of pollen .
Aperture in pollen.
(i) aperture:-
• It is an weak area on the pollen surface which is directly or
indirectly associated with the germination.
• The aperture may be simple or compound, pollen with simple
aperture are either colpate (with colpi- long aperture) or poret (
with pores).
• A compound aperture consists of a central region called oral and
outer region called colpal inculpate pollen and poral with
compound pores.

4. • NPC is an artificial system of classification of pollen or spore based
on 3 features of aperture no, position and character .
• Erdtman and straka 1961 proposed NPC classification and pale ologist
all over the world accepted it.
• According to NPC system each pollen has arithmetic no. consisting
of 3 digits.
• The 1st digit reveals the absence or presence of aperture if presents
the total no. of aperture present in a polen grain.
• Second digit reveals the position of aperture i.e digital , proximal ,
equatorial, latitudinal.
• The 3rd digit explains the character if aperture i.e circular oval or
elongated simle or compound.
• N= no, P = position and C = character of aperture composed of NPC
CLASSIFICATION

5. G. Erdtman

7. classification of aperture based on No.
• The N denotes the no. of aperture present in a pollen grain.
• Pollen having aperture are divided into 7 groups.
• They are mention N1- N7.
• Each group has a characteristic no. aperture.
E.g. N1 has one aperture.
N2 has 2 aperture.
And N7 has 7 or more aperture.
• N 1 to N 7 are refered as monotreme , diatreme, tritreme,
tetratreame, pentatreme, hexatreme, polytreme.
• ‘’Trema’’ in greak means ‘’ hole or opening’’ there are polen grains .
where aperture are absent such pollen grain are called inaperture or
atreme.

8. N are placed under No . group

9. • Another special group N 8 termed as anomotreme is treated
where pollen grains have one or several irregularly spaced
aperture.

10. Classification of aperture based on position:-
• In NPC ‘p’ denotes the position of aperture in a pollen grain there
are 7 groups p0 to P6.
• Pollen grains with P0 group have uncertain or unknown position of
aperture
• P1 groups are catatreme ( kata – down) treme – aperture) P1
• Catatreme pollen grain have one aperture e occurs at proximal parts
of a grain.
• P2 are anacatatreme ( ana – up) .P2
• This group have 2 apertures one at the proximal and other at the
distal pole or distal end.
• P3 are called anatreme ( one at upper).
• These group have 4 aperture at distal position.

11. • P4 are zonotreme .
• Zono refers to equatorial or sub equatorial region
• P5 at dizonotreme where apertures are arranged in 2 or more zones
parallel to the equator.
• P6 are pantotreme ( planto – all or wholley)
• The apertures are scattered all over the surface uniformly.

17. Classification on basic of character
• The character groups of pollen are 7 and they are mension as C0 to C6
• C0 group have aperture which character cant be estrablished with certain unit
C1 groups of pollen have ( leptoma – thin place)
• Leptoma is a thin area aperture like and function as an aperture pollen grains
having one leptoma are called monoleft.
• The leptoma may be proximal or distal and according the pollen the pollen are
proximal – cataleft , distal analeft
• C2 groups are trichotomocolpate.
• Here( tricha -3 parts ) (tome means cut) (colpate means depression or furrow)
• It is a 3 branched aperture the membrane and the branches are more than 2
times longer than the bread.
• C3 cut aperture:- c3 colpate type aperture
• C4 like poret type (like a pore)
• C5 like colporat
• C = pororate

19. • In NPC system a grain in mentioned in 3 digit no.
• E.g. 343 instead of N3 P4p3
• Pollen grain having 343 are N3P4C3
Tritreme zonocolpate N5P5C5 pentatreme dizonocolpate

20. Merits of NPC classification:
• Simple state of classification illustrate the aperture of pollen grain it
makes a presize description with the help of NPC . Pteritophyta ,
monocotyledon, dicotyledon, can be differentiated.
• Identification of pollen grain and spore is the essential prerequisite
applied aspects of palynology.
Demerits
• Its an artificial system of classification syn colpate and para
colpate do not fit in NPC system.
• Eg.Tectona , Agremony

23. 3.Pollen grains that are characteristically present as aggregates in
tetrads, e.g. Ericaceae, Typhaceae and polyads, e.g. Orchidaceae,
Mimosa etc. are not grouped in NPC system.
NPC-system of classification is always compared with Linnaeus’s
system of classification, because the latter is also an artificial
system of classification. The characters of stamen were the basis
of classification.
‘Linnaeus accepted the weakness of his classification but claimed
that it was propounded mainly as an aid to identification’. This is
also applicable to Professor Erdtman. Palynologists from every
discipline of palynology utilize Erdtman’s NPC classification and
other characters related to pollen morphology as an aid to the
identification of unknown sporomorphs.