rachis

“The thickness of the rachis in some specimens is 3 microns thick. That’s less than the size of the average cell,” O’Connor says.

It had a magenta rachis down the center with soft green vanes that shimmered yellow and purple and blue depending on how you turned it.

But this specimen lacked the rachis; it just had barbs and barbules down its ribbonlike tail.

Their structure suggests that the two finest tiers of branching in modern feathers, known as barbs and barbules, arose before the rachis formed.

Fruit.—Fleshy, coalescent and sunk in the rachis.