The small, narrow leaves of Selago triquetra are densely present on upper stems, spreading or reflexed. The leaves are up to 5 mm long and 1 mm wide.
The inflorescences are cylindrical, densely flowered, stem-tip spikes. Long, pointed, green bracts subtend the flowers.
The two-lipped and five-lobed flowers, tubular at the corolla bases, are white, about 5 mm in diameter. Yellow anthers or longer white styles are exserted from some corolla mouths.
Flowering happens from before midwinter to after midspring (Vlok and Schutte-Vlok, 2015; Bond and Goldblatt, 1984; iNaturalist; JSTOR).