Aylostera minor (Rausch) Mosti & Papini

Regarded by some as a diminutive form of Aylostera diersiana, which itself is sometimes regarded as a form of A. pygmaea. Comparatively very small stems with dark areoles and spines make this yellow-flowered plant distinctive. Found to be distinct enough to be given specific status by Mosti & Papini (2011).

The description is here.

Plants of this species in the collection include:

Aylostera minor WR630