Herbs 1.5–10 dm. Leaves glau­cous; basal blades spatulate-obovate to elliptic-oblong, 2–10 cm × 5–20 mm, apex obtuse; cauline blades elliptic-oblong to lan­ceolate or narrowly ovate, 1.5–9(–14) cm × 4–30(–50) mm, distal blades with apices acute to acuminate. Inflo­res­cences: pedicels 3–10 cm. Flowers: calyx 10–25 mm, lobes subulate to linear, apex acuminate; corolla pre­dominantly pale to deep violet-blue or rarely rose-violet, with successive zones of greenish yellow, darker and paler shades of the predominant color in the throat, or rarely white or pale yellow, 1.8–7 cm, lobes elliptic to obovate, apex rounded to subacute, often mucronate.

Discussion

Subpecies 2 (2 in the flora): United States, Mexico, West Indies, Central America; introduced in n South America and Pacific Islands (Guam).

Whether plants of Eustoma exaltatum are annual, biennial, or perennial depends on the amount and distribution of rain during the growing season.

Although the two subspecies recognized here have often been treated as distinct species, observations and measurements in studies for this flora indicate that variation in plant size, leaf shape, flower size, and corolla-lobe shape is essentially continuous and exhibits less correlation with geographic distribution than has been indicated in some publications. Many specimens from New Mexico and Oklahoma, especially, are inter­mediate in morphology.

Selected References

None.

Lower Taxa

Eustoma exaltatum subsp. exaltatum, Eustoma exaltatum subsp. russellianum

Key

1	Corollas 1.8–4(–4.5) cm.	Eustoma exaltatum subsp. exaltatum
1	Corollas (3.5–)4–7 cm.	Eustoma exaltatum subsp. russellianum