Myrmecochorous adaptations ofCorydalis species (Papaveraceae) in southern Japan

Dispersal morphology based on the myrmecochorous adaptations for predator avoidance of sevenCorydalis species including two varieties are investigated in southern Japan. Three types of myrmecochory were distinguished: myrmecochory with autochory (diplochory), the explosive ejection of seeds followed by ant transportation; myrmecochory with vegetative reproduction, seed-transportation by ants and reproduction by tuber; and pure myrmecochory, seed-transporting by ants only. Diplochory occurs in one winter annual plant, which has explosive capsules, a smooth seed surface, a small elaiosome, long pedicels and large bracts. Myrmecochory with vegetative reproduction occurs in two perennials that reproduce by tuber, although they also produce a small number of seeds with a medium-sized elaiosome. the pedicels and bracts are medium in size. Pure myrmecochory occurs in five annuals or biennials that are characterized by a rough seed surface with a large elaiosome, comparatively high seed production, short pedicels and only small bracts. Diplochory is exhibited by only one species distributed widely throughout Japan. Myrmecochory with vegetative reproduction is exhibited by species mainly distributed in cool-temperate northern Japan, while true myrmecochory is exhibited by the majority ofCorydalis species in warm-temperate Japan.