'"Sansai" vegetables are those vegetables that in olden times were harvested from the wild (the "san" in sansai is the Chinese character for "mountain"). In the past there was a clear distiction between these wild vegetables and cultivated vegetables (Japanese "yasai").
Before modern cultivation techniques, sansai was closely associated with Spring, as this was the time that many of these vegetables were available. "Sansai ryori" generally refers to foods that use sansai vegetables. Some of the vegetables most commonly associated with sansai are: fern heads (warabi), Japanese butterbur buds (fuki), mugwort, red garlic and nemagari-take (bamboo grass).