This is a widespread epiphyte which grows into large clumps of canes, the canes sometimes growing over 60cms lomg. When large rainforest trees fall they sometimes bring down large colonies of epiphytes which often includes gracilicaule in conjunction with king orchid (Dendrobium speciosum). In fact, the two species (D. gracilicaule and D. specious) hybridise naturally to form the taxon Dendrobium x gracillimum which occurs in the area, having flower spikes and individual flowers intermediate between D. gracilicaule and D. speciosum.
D. gracilicaule presumably extends widely through the gardens of mosses and epiphytes on the high branches up in the canopy. The flowers are about 15mm across, greenish-yellow with reddish-brown blotches on the outside.