A Grammatical Dictionary of Botanical Latin

Costus,-i (s.m.II), abl.sg. Costo “Spiral-flag. The Latin name is derived from an Oriental name for an imported aromatic root. Zingiberaceae” (Stearn 1996); NOTE the masculine gender: Costus bracteatus, C. bullatus, C. chartaceus, C. cordatus. Gk. kostos, (s.m.II) “root used as spice, Saussurea Lappa, also koston (s.n.II)” (Liddell & Scott)].

Costus afer, Ginger Lily (Zingiberaceae); Costus Luanusianus; Costus spicatus.

Classically Costum-i (s.n.II), abl.sg. costo; also costos,-i (s.f.II), abl.sg. costo: = Gk. kostos “an Oriental aromatic plant: Costus arabicus Linn. (Lewis & Short).

Costaceae (genera): Chamaecostus; Cheilocostus; Costus; Dimerocostus; Monocostus; Paracostus

Saussurea Lappa (syn. Aucklandia costus). Costi amari radix, the root of (bitter) costus, used in ancient Roman trade with India is believed to have been the dried root of Saussurea Lappa (Wikipedia 2021).