The branched stem-tips of Galium tomentosum shown here bear clusters of quite small, pointed-petal, yellow flowers.

The species is dioecious, male and female flowers occurring on different plants. This is unusual for the genus is mostly characterised by bisexual flowers. The stamens occurring in the male flowers are exserted. The ovaries in the female flowers have two locules each, with each containing one ovule.

Shiny as well as hairy upper internodes display fine, longitudinal stem ridges between the leaf whorls (Vlok and Schutte-Vlok, 2015; Shearing and Van Heerden, 2008; Leistner, (Ed.), 2000; iNaturalist; https://www.fernkloof.org.za).