Please, may we know from where the seeds were purchased? Knowing that would help narrow down the possibilities.
In the herbal/accupuncture community something labeled as 'Chinese Plantain Seed' aka Che Qian Zi aka "Semen Plantaginis" can be the mature dried seed of several different types of Plantain:
Plantago afra, P. ovata, P. indica, P. asiatic, P. depressa. (There may be others.)