Feather birds, Oviraptorosauria and Deinonychosauria. In 1998, the discovery of a feathered oviraptorosaurian, "Caudipteryx zoui", challenged the notion of feathers as a structure exclusive to Avialae. Buried in the Yixian Formation in Liaoning, China, "C. zoui" lived during the Early Cretaceous Period. Present on the forelimbs and tails, their integumentary structure has been accepted as pennaceous vaned feathers based on the rachis and herringbone pattern of the barbs. In the clade Deinonychosauria, the continued divergence of feathers is also apparent in the families Troodontidae and Dromaeosauridae. Branched feathers with rachis, barbs, and barbules were discovered in many members including "Sinornithosaurus millenii",
Rachis achieved pachytene and are attached to the walls of the gonadal tube. The rachis is filled with cytoplasm. In plants, a "rachis" is the main axis of a compound structure. It can be the main stem of a compound leaf, such as in "Acacia" or ferns, or the main, flower-bearing portion of an inflorescence above a supporting peduncle. A ripe head of wild-type wheat is easily shattered into dispersal units when touched or blown by the wind. A series of layers forms that divides the rachis into dispersal units consisting of a small group of flowers (a single spikelet) attached