• (a.) Having the seeds straight, as in the fruits of some umbelliferous plants; -- opposed to coelospermous.
Or`tho·sper'mous adjective [ Ortho- + Greek ... seed.] (Botany) Having the seeds straight, as in the fruits of some umbelliferous plants; -- opposed to cœlospermous . Darwin. 
orthospermous Having the seeds straight, as in the fruits of some umbelliferous plants; such as, parsley, carrot, parsnip, and fennel