A cytomorphological investigation of three species of the genus Sonchus L. (Asterales: Asteraceae) from Punjab, India.

Three species of the genus Sonchus L. (Sonchus asper, S. oleraceus and S. wightianus) were collected from the Malwa region of Punjab during 2019 to 2020. These species were studied for cytomorphological variations. The species under investigation were identified based on their morphological descriptions. Sonchus asper (L.) Hill and Sonchus wightianus DC. possess the same number of chromosomes (2n=2x=18) whereas Sonchus oleraceus (L.) L. is tetraploid with 2n=4x=32 chromosomes. Chromosome number of S. wightianus (2n=2x=18) was worked out for the first time from the state of Punjab. Sonchus olereceus has larger pollens than S. asper and S. wightianus. This study will be useful for researchers, taxonomists and cytologists for accurate identification of these three species. [ABSTRACT FROM AUTHOR]