楸
Meanings
1
yellow catalpa; Chinese catalpa
archaic
Archaic name for Catalpa ovata, a tree with large leaves and showy flowers. In modern Japanese, this tree is usually called キササゲ.
See also: キササゲ
In old documents, the catalpa is written as 楸.
2
archaic
Archaic name for Mallotus japonicus, a shrub or small tree with large leaves. The modern common name is 赤芽柏 (アカメガシワ).
See also: 赤芽柏
久木 is an old word that referred to the Japanese mallotus.