Grammatophyllum speciosum var. flava
Also known as tiger orchid, considered the largest orchid species in the world!
Size: As pictured, blooming size, bareroot.
Care: Grammatophyllum speciosum var. flava should be in bright light to full sun with frequent watering/fertilizing in the summer, reduced waterings as temperature falls. 
Grammatophyllum speciosum is a rare species native to South East Asia that can grow to over 6ft tall making great specimens. This group is the even rarer flava form which produce pure yellow blooms as opposed to the traditional yellow and brown blooms. A must-have for all rare and giant orchid collectors!