Xochiquetzallia is a genus of geophytic flowering plants of the subfamily Brodiaeoideae in the family Asparagaceae.[1][2] The genus contains four species: three previously classified within the genus Dandya and one other previously classified within Milla. Earlier genetic and morphological research had shown that the broad Milla clade of plants is made up of two sister lineages.[3] The four plant species now within Xochiquetzallia make up one of these lineages, and are more closely related to each other than they are to the second lineage, which is made up of the remaining Milla species, Dandya purpusii, and the genera Behria, Bessera, Jaimehintonia and Petronymphe.[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.[1]
Xochiquetzallia species are herbaceous perennials, growing from corms. They can be distinguished from related genera by the combination of two floral characteristics. The gynophore of a Xochiquetzallia flower lacks pith and the stigma is entire (undivided). Other genera in the Milla clade have pith in the gynophore and a divided stigma.[4]
Plants in this genus are between 20 cm and 60 cm high from the base of the corm to the top of the flowerhead. Their roots are fibrous and sometimes fleshy, emerging from a corm in the shape of a flattened ball that is between 1.0 cm and 2.5 cm in diameter. There are 5–9 narrow, dark-green leaves, each 20–49 cm long from the blunt base to the acute tip. In cross-section they may be flattened or somewhat circular (terete). The surface may be smooth (glabrous) or scaly (scabrous), with translucent projections along the leaf veins. 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.[5]
The inflorescence is in the form of an umbel on top of a scape that is generally 20–50 cm long. This scape is cylindrical, usually shorter than the leaves, with a surface that is smooth with occasional acute prominences. Below the umbel there are 2–3 narrowly triangular bracts 3.0–9.0 mm long. There is also a single bracteole below each of the 4–20 flowers. The flowers are borne on pedicels 0.8–3.5 cm long arising from the top of the scape. 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.[5]
Flowers of Xochiquetzallia species are white or blue. Each begins with a tube (where the tepals are fused) that is 1–25 mm long. Like all lilioid monocots, the flowers have six tepals, arranged in two groups of three. Each outer tepal is elliptic in shape with a narrowing base, acute tip and 1–3 veins; these outer tepals measure 8.0–16.0 mm long and 2.0–7.0 mm wide. The inner three tepals are similar, but sometimes more broadly elliptical and with more obtuse tips; these inner tepals measure 8.0–16.0 mm long and 3.0–11.0 mm wide. The flower has six separate fertile stamens, each arising from a corresponding tepal near the throat of the floral tube. The stamen filaments are typically 2.0–5.0 mm long and may be thread-like or widen somewhat toward the base. Each of the six yellow anthers is 1.0–2.5 mm long and is basifixed (attached by its base to the stamen filament). The anthers taper towards the tip and sometimes towards the base as well.[6]