A Grammatical Dictionary of Botanical Latin

-tropis,-idis (s.f.III), abl. sg. -tropide: in Gk. comp. ‘keel, keeled;’ “the keel of a papilionaceous flower, or any part resembling it” (Lindley) [> Gk. tropis,-idis (s.f.III) a ship's keel = tropideion (s.n.II)]; = L. carina,-ae (s.f.I), q.v.; see keeled;

Microtropis,-idis (s.f.III), with a small keel; Oxytropis,-idis DC. (s.f.III), gen. sg. Oxytropidis, dat. sg. Oxytropidi, abl. sg. Oxytropide, > Greek oxus, sharp + tropis, ship's keel; “an allusion to the form of the flower. Leguminosae.” (Stearn 1996).

FABACEAE (epithets): amblytropis, with a blunt keel; brachytropis, with a short keel; iodotropis, with a violet keel; lasiotropis, with a wooly or hairy keel; macrotropis, with a great keel; megalotropis, with a large keel; plagiotropis, with a slanting kee l; platytropis, with a broad or wide keel; plectotropis, with a twisted keel; pogonotropis, with a bearded keel; rhynchotropis, with a beaked (projecting) keel; schizotropis, with a cleft or split keel; ulotropis, with a hair-thin or shaggy keel.

NOTE: cf. carina,-ae (s.f.I): a keel. The two anterior petals of a papilionaceous flower, the three anterior in a Milkwort [Polygala vulgaris L. or Polygala spp.], or any such” (Lindley); “a keel; used either for the two combined lower petals of a papillionaceous corolla” (Fernald 1950).