Manfreda and close relatives have long presented significant
taxonomic difficulty. With the advent of
DNA sequencing, new
karyologic and evolutionary
phylogenetic studies showed that
Manfreda, along with
Polianthes and
Prochnyanthes, were genetically nested within the traditional circumscription of
Agave, rendering that genus
paraphyletic. Early in the 21st century, these new phylogenetic results led to a reclassification of to include
Manfreda,
Polianthes and
Prochnyanthes together as
Agave subgenus
Manfreda. There was reaction against the changes from those who noted that the large
morphological differences between the genera in this new
Agave s.l. making them "counter-intuitive from a horticultural point of view".
Manfreda morphologically differs from the classic
Agave description in being
herbaceous and
bulbous. Thus, based on a wider consideration of previously established genetic, morphological, and estimated genetic divergence times, Vázquez-García et al. proposed a narrower circumscription of
Agave, paving the way for a reconsideration of
Manfreda as a genus. ==Species==