BRACTEOLE: a small bract-like structure borne singly or in pairs on the pedicel or calyx of a flower.
The shape and length of the bracteoles in Costus are sometimes used to distinguish between species. There are two types of bracteoles - unicarinate and bicarinate. The most typical type is the unicarinate, or "boat shaped" bracteole. Costus with boat shaped (unicarinate) bracts are marked "Y". Costus with bicarinate bracts are marked "N". If this characteristic is unknown it is entered in the GingersRus Plant Database as "U".

EXAMPLE #1 - BOAT SHAPED BRACTEOLES
Examples of unicarinate bracteole


EXAMPLE #2 - NOT BOAT SHAPED (BICARINATE)
Examples of bicarinate bracteoles