Scope of the genus and its place in the family
POWO accepts one species, Blossfeldia liliputana. The names B. atroviridis, B. campaniflora, B. fechseri, B. minima and B. pedicellata are its synonyms. In this treatment, historical descriptions of different appearances therefore represent variation within one species. [2-WWW]
In 2006, Butterworth checked for an intron in the chloroplast gene rpoC1. An intron is a segment transcribed from DNA and removed during RNA maturation. This segment was present in Blossfeldia but absent in the other examined members of Cactoideae as then circumscribed. The result provided additional support for the distinct position of the genus, previously indicated by Nyffeler's sequence analysis. The author established the tribe Blossfeldieae at that time. [Butterworth 2006, p. 3–10]
In the 2025 classification by de Vos and colleagues, the genus forms a separate subfamily, Blossfeldioideae, sister to Cactoideae in its narrower circumscription. This arrangement builds on earlier chloroplast analyses. Small size and a simplified stem surface are features of a present-day, independent evolutionary lineage. [de Vos et al. 2025, de Vos et al., sections on Blossfeldioideae and classification] [Nyffeler 2002, de Vos et al., sections on Blossfeldioideae and classification]
Structure and water relations
The stems are flattened, without distinct ribs or spines. Hair-bearing areoles lie in spirals on the surface of the body. A thin covering layer, a predominance of parenchyma and the structure of conducting elements accompany large changes in volume during drying. Stomata are concentrated in depressions associated with the areoles. [Barthlott and Porembski 1996, pp. 161–165]
A drying experiment lasting several years showed that plants retained the ability to rehydrate at a very low mass. The data and the meaning of poikilohydry are described in the article on dehydration in Blossfeldia. Flower and seed structure and the results of in vitro propagation are presented in the species profile. [Barthlott and Porembski 1996] [Ivannikov et al. 2022]