Answer: rachides

AnswerCrossword Clue
rachidesa. the axis of an inflorescence when somewhat elongated, as in a raceme b. (in a pinnately compound leaf or frond) the prolongation of the petiole along which the leaflets are disposed c. any of various axial structures
rachidesRACHIS, the spinal column, also RHACHIS
rachidesthe part of the shaft of a feather bearing the web