Earlier genetic and morphological research had shown that the broad Milla clade of plants is made up of two sister lineages.

[3] Jorge Gutiérrez and Teresa Terrazas, two of the botanists who worked on the earlier research, followed up in 2020 with a paper formally transferring the four species from Dandya and Milla to Xochiquetzallia.

The lower portions of the leaves arising from the corm form a brown tunic that surrounds the base of the scape (flower stalk) for up to 2.0 cm.

In form they are either subcampanulate (broadly bell-shaped) or hypocrateriform (shaped like a salver on top of a narrow tube) and they are either held erect or droop somewhat from the tip of the pedicel.

The fruit forms as a roughly ball-shaped or cylindrical, smooth-surfaced, brown, three-sided capsule 6.0–13.0 mm long.

Inside are shiny black oblong or sickle-shaped seeds with a bumpy surface that are about 4.0 × 1.5 mm in size.

The Milla clade is estimated to have arisen approximately 15.8 Ma (15.8 million years ago) in the California Floristic Province, separating from the lineage that gave rise to the other eight genera within Brodiaeoideae.

Specimen records indicate that X. mortoniana and X. hannibalii grow in the lower reaches of the Río Balsas valley, in the states of Michoacán and Guerrero.

X. mortoniana was originally collected on the edge of cliffs at 1400 m elevation at Tierras Blancas, in Mina district of Guerrero.

X. hannibalii was originally recorded growing singly (rather than in clumps) in full sun and very light shade in gritty red soil on dry rocky hillsides facing west, in short grass near giant cacti.

The species was originally recorded in large colonies in part shade and full sun on hillsides with calcareous soil, growing under thorny shrubs and giant Neobuxbaumia tetetzo cacti.

[14][15][16] Subsequent analysis did show that one population of X. balsensis, from an upland area in the state of Morelos, can be distinguished from X.