Nyctaginaceae, the four o'clock family, is a family of around 33 genera and 290 species of

flowering plant Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (), commonly called angiosperms. The term "angiosperm" is derived from the Greek words ('container, vessel') and ('seed'), and refers to those plants t ...

s, widely distributed in tropical and subtropical regions, with a few representatives in temperate regions. The family has a unique fruit type, called an "

anthocarp An accessory fruit is a fruit in which some of the flesh is derived not from the floral ovary but from some adjacent tissue exterior to the carpel.Esau, K. 1977. ''Anatomy of seed plants''. John Wiley and Sons, New York. Accessory fruits are us ...

", and many genera have extremely large (>100

µm The micrometre ( international spelling as used by the International Bureau of Weights and Measures; SI symbol: μm) or micrometer ( American spelling), also commonly known as a micron, is a unit of length in the International System of Uni ...

) pollen grains. The family has been almost universally recognized by plant taxonomists. The

APG II system The APG II system (Angiosperm Phylogeny Group II system) of plant classification is the second, now obsolete, version of a modern, mostly molecular-based, system of plant taxonomy that was published in April 2003 by the Angiosperm Phylogeny Gr ...

(2003; unchanged from the

APG system The APG system (Angiosperm Phylogeny Group system) of plant classification is the first version of a modern, mostly molecular-based, system of plant taxonomy. Published in 1998 by the Angiosperm Phylogeny Group, it was replaced by the improved A ...

of 1998), assigns it to the order

Caryophyllales Caryophyllales ( ) is a diverse and heterogeneous order of flowering plants that includes the cacti, carnations, amaranths, ice plants, beets, and many carnivorous plants. Many members are succulent, having fleshy stems or leaves. The betalai ...

in the clade

core eudicots The eudicots, Eudicotidae, or eudicotyledons are a clade of flowering plants mainly characterized by having two seed leaves upon germination. The term derives from Dicotyledons. Traditionally they were called tricolpates or non-magnoliid dicots ...

. A phylogenetic study by Levin has justified the combination of ''Selinocarpus'' and ''Ammocodon'' into the genus ''

Acleisanthes ''Acleisanthes'' is a genus of flowering plants in the ''Bougainvillea'' family, Nyctaginaceae. There are currently 16 species. The generic name is derived from the Greek words ακλειοτος (''akleistos''), meaning "not closed", and ανθ� ...

''. The genus ''Izabalea'' is now considered a synonym of '' Agonandra'', a genus in Opiliaceae. A more recent study by Douglas and Manos clarified the relationships among almost all of the genera in the family and demonstrated that a substantial diversification of herbaceous genera has occurred in arid North America. Many genera of Nyctaginaceae possess unusual characters. Notable examples include sticky bands on the stems between the nodes, cleistogamous flowers (which self-pollinate without opening), or gypsophily, the ability to grow on soils with a high concentration of

gypsum Gypsum is a soft sulfate mineral composed of calcium sulfate dihydrate, with the chemical formula . It is widely mined and is used as a fertilizer and as the main constituent in many forms of plaster, blackboard or sidewalk chalk, and drywa ...

Genera

The extinct genus '' Mennegoxylon'' has been provisionally placed in the family. Note; as of February 2022,

Plants of the World Online Plants of the World Online (POWO) is an online database published by the Royal Botanic Gardens, Kew. It was launched in March 2017 with the ultimate aim being "to enable users to access information on all the world's known seed-bearing plants by ...

classes ''Boldoa'' as a synonym of ''Salpianthus'' and ''Grajalesia'' as a synonym of ''Pisonia''.

Uses

The family contains one food crop, the mauka (''Mirabilis extensa''), a

root vegetable Root vegetables are underground plant parts eaten by humans as food. Although botany distinguishes true roots (such as taproots and tuberous roots) from non-roots (such as bulbs, corms, rhizomes, and tubers, although some contain both hypocoty ...

of minor local importance in the

Andes The Andes, Andes Mountains or Andean Mountains (; ) are the longest continental mountain range in the world, forming a continuous highland along the western edge of South America. The range is long, wide (widest between 18°S – 20°S ...

. Garden Four-O'Clocks '' Mirabilis jalapa'' species are grown as

ornamental plant Ornamental plants or garden plants are plants that are primarily grown for their beauty but also for qualities such as scent or how they shape physical space. Many flowering plants and garden varieties tend to be specially bred cultivars that ...

s, as are species of ''

Bougainvillea ''Bougainvillea'' ( , ) is a genus of thorny ornamental vines, bushes, and trees belonging to the four o' clock family, Nyctaginaceae. It is native to eastern South America, found from Brazil, west to Peru, and south to southern Argentina. ...

'' (''Bougainvillea glabra, B. spectabilis'', and numerous hybrids), ''

'' and '' Abronia'' are commonly cultivated in warmer regions.

References

*Levin, 2000, Phylogenetic relationships within Nyctaginaceae tribe Nyctagineae: Evidence from nuclear and chloroplast genomes. Systematic Botany 24(4) 738-750. (Subscription req.) *Douglas, NA and Manos, PS. 2007. Molecular phylogeny of Nyctaginaceae: taxonomy, biogeography, and characters associated with a radiation of xerophytic genera in North America. American Journal of Botany 94(5) 856-872.

External links

Nyctaginaceae
in L. Watson and M. J. Dallwitz (1992 onwards)
''The families of flowering plants''

''Flora of North America'': NyctaginaceaeNCBI Taxonomy Browserlinks at CSDL
{{authority control Caryophyllales families