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Four-o'clock family
Nyctaginaceae Juss.
オシロイバナ科
A family of about 400 species distributed mainly in tropical and subtropical regions. In Japan, Mirabilis jalapa (four o'clock flower, from South America) is widely naturalized and cultivated. The family is characterized by the absence of petals, with petal-like sepals appearing as the 'flower.' Bougainvillea is a famous ornamental in this family.
Key Characteristics
- ●Petals absent; conspicuous petal-like sepals serve as the perianth
- ●Bracts may become petal-like (e.g., Bougainvillea)
- ●Fruit is an achene enclosed in the persistent calyx tube
- ●Leaves are simple, opposite or alternate
Morphological Traits
A family may include species with different trait values — multiple values indicate the range within the family.
Leaf arrangement
Alternate / Opposite
Leaf type
Simple
Venation
Pinnate
Leaf margin
Entire
Growth form
Shrub / Tree / Vine / Herb
Evergreen/Deciduous
Deciduous
Leaf dissection
Undivided
Stipules
Absent
Flower symmetry
Actinomorphic
Petal count
3 petals
Petal fusion
Fused
Ovary position
Superior
Stamen count
3-4
Plant sex
Hermaphrodite / Monoecious
Phylogenetic Position
Angiosperms > Eudicots > Core Eudicots > Caryophyllales > Nyctaginaceae
Divergence Era
Paleogene (ca. 55 million years ago)
Representative Genera
Related Evolution Events
- ・Morphological transformation of flowers through loss of petals and petaloid sepals
- ・Innovation in pollinator attraction through petaloid bracts (Bougainvillea)
Plants in Four-o'clock family on this site
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