The Nyctaginaceae are herbs, shrubs, and trees comprising 30 genera and 300 species further characterized by the presence of betalains and p-plastids. The leaves are simple, entire, estipulate, and usually opposite. The flowers are usually bisexual, have a 3-8-lobed uniseriate perianth of connate, petaloid sepals and are subtended by bracts that range in appearance from large and brightly colored to reduced and calyx-like. The androecium consists of 1-30 hypogynous, commonly unequal stamens that may be free or connate into a basal tube. The gynoecium is a single simple pistil with a superior ovary containing one locule and one basal ovule. The fruit is an achene that is often enveloped by the persistent base of the calyx tube.

Each "thumbnail" image below is linked to a larger photograph.

Abronia mellifera, sand verbena, W of Pasco, WA, 2002.
Abronia villosa, sand verbena. Note the corolla-like nature of the tubular calyx.
Allionia incarnata, trailing windmills, this seemingly actinomorphic "flower" is actually an inflorescence consisting of three tightly clustered zygomorphic flowers, vic. Tucson, AZ, March, 2004.
Boerhavia repens, alena. Dispersal of this native plant to Hawaii by birds was aided by the glandular-stickiness of the persistent calyx tube on each of the accessory fruits seen in the first photo.
Bougainvillea spectabilis. Large woody vine, native to Brazil, flowers are grouped in cymes of 3, and each flower has a brightly colored subtending bract.
Mirabilis jalapa, four-o-clock. In this case the calyx is very much like a corolla and the bracts subtending the flower closely mimic a calyx.
Pisonia brunoniana, papala. Notice the uniseriate perianth. This Hawaiian native species has very sticky fruits (lower photo) that were used by the Hawaiians to capture birds so feathers could be collected for ornamentation.

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