Sometimes incorrectly known as lesser galangal, the botanical name of this ginger-like root is Kaemferia galanga. The correct english name, rarely encountered, is zedoary.
Kencur has a unique, camphor-like, flavour and should be used sparingly. Wash it and if you're fussy (most Indonesians aren't) scrape off the skin before using. Dried sliced kencur (sometimes spelled kentjoer) or kencur powder can be used as a subtitute. Soak dried slices in boiling water for 30 minutes; use ½ - 1 teaspoon of powder for 2½ cm (1 in) fresh root.