Pollen morphology of four different species,
Sonchus uliginosus, S. arvensis, S. asper, S. maritimus, S. oleraceous
& S. palustris, belonging to genus Sonchus of family
Asteraceae was studied from Pakistan. Morphology of pollen grains of
each of the species is based on specimens selected at random. Proposed
characters i.e. grain class, shape of pollen grain, equatorial view,
polar view, equatorial diameter (E), polar diameter (P), P/E ratio,
length of colpus, exine surface, exine thickness, inter poral distance,
inter spinal distance, inter spinal outline, length of spines, number
of spines between colpi in each species were recorded for comparison.
At species level, micromorphological differences and distribution of
surface pattern, shape and size of pollen have been found to exist.
The pollen grain are tetrazonocolporate. Maximum spine length, exine
thickness, colpus length was observed in Sonchus uliginosus.
Sonchus oleraceous has studies in distinguishing some taxonomic
groups in the Asteraceae.