The trifoliolate leaves of Aspalathus araneosa consist of slender or weak, linear to thread-like leaflets, usually curved. They are sparsely covered in spreading, long hairs based on tubercles.
The inflorescence is a dense, stem-tip head of up to 15 yellow flowers. There are floral bracts, mostly also trifoliolate and long-haired like the leaves, grown on short stalks next to the hairy pedicel. The calyx tube is pale, ending in linear to thread-like, hair-fringed lobes.
The banner petal is broadly obovate with rounded tip and short hairs on its outside. The wing petals are narrowly ovate and the keel petals crescent shaped. The ovary is hairy or partly so.
The fruit pod becomes 6 mm long and 3 mm wide. It is dark when ripe and at least partly woolly (Bond and Goldblatt, 1984; Kidd, 1983; JSTOR; iNaturalist).