A Grammatical Dictionary of Botanical Latin

-gonum,-i (s.n.II), abl.sg. –gono, also –gonon,-i (s.n.II), abl.sg. –gono in Gk. comp.: knee, bend, angle, joint; cf. -gonE,-es (s.f.I);

NOTE: the Greek –on ending is equivalent to the Latin –um ending (second declension neuter nouns).

NOTE: as some of the etymologies below indicate, there is confusion about the stem of this suffix, whether it reflects Greek ‘gonos (s.m.II), that which is begotten; or gonE (s.f.I), offspring or, as is probably correct, Gk. ‘gonu, (s.n.III), gen.sg. gonatos, knee, the joint of plants.

As most of the following genera are in the Polygonaceae, the –gonum endings more likely relate to (such) a joint, bend, etc. and the etymology seems controlled by botanical usage more than linguistics.

NOTE: there is no ending –gonum in Latin. The Latin noun for ‘knee’ is genu,-us (s.n.IV), a fourth declension neuter noun, like Lat. cornu,-us (s.n.IV), ‘horn.’

Acongonon (Polygonaceae): possibly from Gk. akE (s.f.I), ‘point’, cf. Gk. akis,-idos (s.f.III), a pointed object; hence, needle, splinter, the barb of an arrow or hook (after Liddell & Scott). Related might be Gk. akonE (s.f.I), a whetsone, hone, that is, an object used to sharpen something + -gonum, derived from Gk. gonu (s.N.II) i.e. with sharp angles or joints; the stem of some of these plants appear to be sharply bent at the joints in a zig-zag fashion.

Antigonon,-i (s.n.II) (Polygonaceae): “Greek, perhaps referring to jointed character of fl.-sts.”[= flower stems or stalks] (Bailey).

Calligonum,-i (s.n.II), “derived from kalos, beautiful and gonum, a joint; there being joints instead of leaves’ Polygonaceae (Paxton).

Chrysogonum,-i (s.n.II) L. > Gk. chrysos, golden, and gonu, knee, from the yellow rays and geniculate stem," (Fernald 1950); > Gk. chrysos, gold, + gonu, a knee, “the flowers are generally produced at the joints of the stem. Asteraceae” (Paxton).

Eriogonum,-i (s.n.II), from Gk. erion, wool + gonu, knee, “from the wooly stems and leaves and swollen joints of the plants” (Fernald 1950) (Polygonaceae).

Polygonum,-i (s.n.II) L. [> Gk. poly, many, and gonu, knee or joint, from the thickened joints of the stem (Fernald 1950)] (Polygonaceae).

Ripogonum > Gk. ripos, a flexile twig, wickerwork + gonu, joint, in reference to the jointed appearance of the stems. Smilaceae” (Paxton).

Sarcogonum,-i (s.n.II) > Gk. sarx, flesh + gonu, a joint. (Paxton); a synonym of Polygonum.

Thelygonum,-i (s.n.iI) > Gk. thelys, woman + gonu, a knee; “supposed resemblance in the joints. Chenopodiaceae” (Paxton) (Rubiaceae).