Mirabilis

The true garden four-o’clock, Mirabilis jalapa L., native to Latin America, rarely escapes from cultivation and apparently has not done so in Michigan. It has a perianth at least 2 cm long and 1-flowered, cup-shaped, herbaceous involucres that do not change in fruit. In our species, the perianth is less than 1.2 cm long and the cup-shaped involucres enlarge, broaden, and become papery as the fruit matures. Occasionally young plants will have only axillary involucres, on slender peduncles, giving them quite a different aspect from larger plants with a ± dense terminal cymose inflorescence.

1. Leaf blades linear, less than 5 mm wide; middle and lower internodes (if not all) glabrous.

M. linearis

1. Leaf blades broader, lance-ovate to deltoid; middle and lower internodes glabrous or pubescent.

2. Middle and lower internodes pubescent, at least in strips; peduncles and involucres with some glandular hairs; blades of principal leaves lance-ovate to lance-oblong, nearly or quite sessile.

M. albida

2. Middle and lower internodes glabrous or nearly so; peduncles and involucres glabrate to pubescent with non-glandular hairs; blades of principal leaves broadly ovate to deltoid, on distinct petioles ± 1 cm or more long.

M. nyctaginea