Pollen grains are distinguished primarily by their form and their surface sculpture. The following Key distinuishes 17 basic pollen classes.

A. Pollen in groups of four grains..TETRADS

AA. Pollen in groups of more than four grains..POLYADS

AAA. Pollen grains free

BB. Aperture one or grain without apertures

C. With bladders or meridional ridges

D. With bladders.............................VESICULATE

DD. With deep meridional ridges..............POLYPLICATE

CC. Without bladders or meridional ridges

D. No distinct apertures.....................INAPERTURATE

DD. One aperture

E. Aperture elongate.....................MONOCOLPATE

EE. Aperture +/- circular................MONOPORATE

BB. More than one aperture

C. Without lacunae in a fixed geometrical pattern

D. Apertures not fused

E. Furrows present, no free pores

F. Furrows without distinct pores or transverse furrows

G. Three furrows..................TRICOLPATE

GG. More than three furrows

H. All furrows meridional....STEPHANOCOLPATE

HH. Furrows not meridional....PERICOLPATE

FF. Furrows with distinct pores or transverse

G. Three furrows..................TRICOLPORATE

EE. Three pores present, no furrows

F. Three pores.......................TRIPORATE

FF. More than three pores

G. Pores in an equatorial zone....STEPHANOPORATE

GG. Pores evenly distributed......PERIPORATE

DD. Apertures fuses to rings etc. ...........SYNCOLPATE

CC. With lacunae in a fixed geometric pattern

D. Lacunae elongate (pseudocolpi)............HETEROCOLPATE

DD. Lacunae not elongate.....................FENESTRATE

You can take a look at this site: http://stri.si.edu/sites/roubik/

There you can find many plates of pollen, so you possibility can indentify them.

I hope I helped you!

There are many book with pollen  illustrations. I can show some  for you:

Barth, O.M. 1989. O pólen no mel brasileiro. Luxor, Rio de Janeiro. 150p.

Erdtman, G. 1966. Pollen Morphology and plant taxonomy - Angiosperms. Hafner Publishing Company. New York and London. 553p.

Moore, P.D.; Webb, J.A. 1978. An illustrated guide to pollen analysis. (Biological science texts).Hodder and Stoughton, London. 133p.

Pirani, J.R.; Cortopassi-Laurino, M. 1994. Flores e abelhas em São Paulo. 2ed. São Paulo, USP/FAPESP. 192p.

Roubik, D.W. & Patiño, J.E.M. 1991. Pollen and spores of Barro Colorado Island. Missouri Botanical Garden, 268p.

Salgado-Labouriau, M.L. 1973. Contribuição à palinologia dos cerrados. Acad. Bras. de Ciên., Rio de Janeiro, 291p.

Sawyer, R. 1988. Honey identification. Cardiff Academic Press, Bristol. 115p.

Ybert, J. P. 1979. Atlas de pollens de Côte D’ivoire. ORSTOM, Paris. 249p.

I would try to find a more regional pollen flora, from India, Taiwan or Pakistan.

Go to Google and type in "Pollen Flora of Pakistan" You will find a list of downloadable pdf files for the various plant families. The files have descriptions, SEM photos etc. I counted roughly 18 or more pdf files there. Have fun. Attached is one example.

there is a book writhed in China but I don´t know the reference. I will find and send to you the reference.

The Chinese pollen flora is in Chinese, but there is the Pollen Flora of Taiwan which is in English...

http://www.amazon.com/Pollen-flora-Taiwan-Tseng-Chieng-Huang/dp/B0007AGNG8

literature is full of pollen identification keys, I think it will be wise to focus on regional pollen keys and, if available from your country

You can email images for identification on the following email address

[email protected] or if your file size is small then on [email protected]

You can also follow as proposed by Ruta B. Limaye above

Can you share pollen slide images for identification??

Erdtman, G., Handbook of Palynology

this book is the best....