Alpinia species ?- Gangtok, Sikkim

Zingiber for id : 8 posts by 4 authors. Attachments (2).
Please identify this Zingiber plant.
Location:- Gangtok, Sikkim,
April - 2015
Leaves apprxtly 1ft in size glossy on upper surface  & waxy on underside.
Alpinia officinarum 
... is right
The photos are too insufficient for identification.
would ... tell me what to photograph in gingers for definitive id
monsoon is coming and many Gingers would be coming up
guide lines would help me