In a fractal-like reflection of the branched rachis and barbs, the barbs themselves are also branched: a series of paired filaments called barbules are fused to the main shaft of the barb, the ramus.

• 羽枝本身也有分支，就像是碎形般重复羽轴与羽枝的分支型态，由一系列称为羽小枝的成对细丝融接到羽枝的主枝上。