Smith, G.F. 2026. Crassula shanelleae (Crassulaceae subfam. Crassuloideae), species status for C. arborescens subsp. undulatifolia from the Eastern Cape province, South Africa. Phytotaxa. 760, 3 (Jun. 2026), 217–229. DOI:https://doi.org/10.11646/phytotaxa.760.3.2.