Phrymaceae, also known as the lopseed family, is a small family of flowering plants in the order Lamiales. It has a nearly cosmopolitan distribution, but is concentrated in two centers of diversity, one in Australia, the other in western North America. Members of this family occur in diverse habitats, including deserts, river banks and mountains.
Phrymaceae is a family of mostly herbs and a few subshrubs, bearing tubular, bilaterally symmetric flowers. They can be annuals or perennials. The floral structure of Phrymaceae is variable, to such an extent that a morphological assessment is difficult. Reproduction is also variable, being brought about by different mating systems which may be sexual or asexual, and may involve outcrossing, self-fertilization, or mixed mating. Some are pollinated by insects, others by hummingbirds. The most common fruit type in this family is a dehiscent capsule containing numerous seeds, but exceptions exist such as an achene, in Phryma leptostachya, or a berry-like fruit in Leucocarpus.
The family Phrymaceae is mainly defined by the following three characteristics:
Tubular, toothed calyces (with five lobes).
Stigmas with two lamellas that have sensitive inner surfaces, that close together on contact with a pollinator.
Capsules that are loculicidally dehiscent, splitting between the partitions of the ovary.
The composition of Phrymaceae and the delimitation of genera changed radically from 2002 to 2012 as a result of molecular phylogenetic studies. Previously, Phrymaceae had been monotypic with Phryma leptostachya as its only species. It was limited in geographic range to eastern North America and eastern China. Phryma had been previously placed by Cronquist in Verbenaceae. Research on phylogenetic relationships revealed that several genera, traditionally included in Scrophulariaceae, were actually more closely related to Phryma than to Scrophularia. These genera became part of an expanded Phrymaceae. Mazus and Lancea were included in Phrymaceae for a short time before further studies indicated that they, along with Dodartia should be segregated as a new family, Mazaceae. A