Translation guide
The central shaft of a compound leaf or inflorescence; also refers to the spine of a feather. In Japanese, different terms are used depending on the context (botany vs. ornithology).
The main stem or axis of a compound leaf (e.g., fern frond, palm leaf) or the central stalk of an inflorescence.
General term for the rachis of a compound leaf. Used in botanical contexts.
The sporangia are attached to the rachis of the fern.
The central shaft or spine of a feather, from which the barbs extend.
The standard term for the rachis of a feather.
Specifically the rachis of an inflorescence (flower cluster).
The rachis of this plant's inflorescence grows long.
Literally 'central axis', can be used for rachis in a broader sense, but less specific than 葉軸.
The leaflets are arranged along the central axis of the leaf.
羽軸が折れた羽は飛ぶのに支障がある。
A feather with a broken rachis hinders flight.
Another term for the shaft of a feather, sometimes used interchangeably with 羽軸, but can also refer to the quill (calamus).
The base of the feather shaft is embedded in the skin.