A pollen morphological investigation of eleven
species and one subspecies of the genus Galium L.
from Egypt were undertaken by using light microscope
(LM) and scanning electron microscope
(SEM). Pollen shape, size, exine ornamentation,
number of apertures present powerful characters for
distinguishing between species. The pollen grains
were zonocolpate. The number of colpi ranges from
5 to 10. Their shape varies from prolate spheroidal,
oblate spheroidal, spheroidal to suboblate. Three
groups can be distinguished based on the size pollen
grains. It was found used to distinguish between
closely related species G. aparine and G. spurium
and between G. tricornutum and G. ceratopodum.
Two different types of exine ornamentation were
recognized. The ornamentation was found useful to
distinguish among closely related species such as
Galium aparine and G. spurium. A key for the identification
of the investigated taxa based on pollen
grains characters is provided.