Mostarda

Two crucifers are known by this name in Madeira: Brassica Sinapistrum and B. nigra. It is the latter species that produces the seeds with which mustard plasters are prepared. B. nigra has siliques with 1-nerved valves: B. Sinapistrum has them with 3-5 nerved valves. Both of these species are spontaneous and frequent in Madeira. The mustard used as a condiment is mainly supplied by the species Sinapis alba, a very rare species in Madeira.