On offer is an advanced, Dendrobium (syn Dockrillia) cucumerinum ‘Polski Ogorki’ x ‘Summer Day’ seedling established on a brown treefern mount.
D. cucumerinum is an Australian native species that is commonly known as the Cucumber Orchid. Preferring a shadier location, and to grow on a mount/raft, mature plants reward their owners with blooms from Summer into Autumn, when little else is in flower. This species resents being kept too wet, so make sure you allow plants to dry out between waterings.
The photographs show examples of both the D. cucumerinum parent flowers, and a seedling typical of those on offer.