Smith, G. F. Refinements to the Infra-Sectional Classification of Kalanchoe [subg. Bryophyllum] Sect. Invasores (Crassulaceae Subfam. Cotyledonoideae) at the Rank of Series: Description of K. [subg. Bryophyllum Sect. Invasores] Ser. Invasores, K. [subg. Bryophyllum Sect. Invasores] Ser. Fruticosa, and K. [subg. Bryophyllum Sect. Invasores] Ser. Herbacea. Phytotaxa 2025, 698, 196-208.