Crassula expansa subsp. filicaulis is a short-lived succulent herb with many branches. The plant appears small and delicate. It reaches a height of 30 cm when in flower, but it is often much shorter. It grows into a bushy shape with some prostrate branches that tend to root at the nodes. These side-roots appear stilt-like.
The maroon red leaves seen here are green or yellowish green in some plants, sometimes with red tips. The leaves are succulent, shiny and hairless. Their shape is cylindrical or barrel-like, attenuating to soft sharp tips. Leaves may become 4 mm long and 3 mm wide in their middle sections. There may be longitudinal grooves on the upper sides of the leaves as can be seen on this specimen from the coast at Vermont near Hermanus (Vlok and Schutte-Vlok, 2010; Bond and Goldblatt, 1984; Mustart, et al, 1997).