Arachnothryx is a genus of flowering plants in the family Rubiaceae. It contains about 107 species. It is found from Mexico to Peru and in Trinidad.

Taxonomy

Arachnothryx was named by Jules Émile Planchon in 1849. This generic name is derived from Ancient Greek: arachne or arachnos, "a spider", and thrix or trichos, "hair". As currently circumscribed, Arachnothryx is paraphyletic over Cuatrecasasiodendron, Gonzalagunia, and Javorkaea. Some authors have included these genera in a broadly defined Rondeletia, but molecular phylogenetic studies have shown that they are more closely related to Guettarda than to Rondeletia.

Species