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Mitrastemon family
Mitrastemonaceae Makino
ヤッコソウ科
A monogeneric holoparasitic family comprising only 2 species of Mitrastemon. They parasitize roots of oaks and chinquapins (Fagaceae) and lack chlorophyll. In Japan, Mitrastemon yamamotoi grows in evergreen broad-leaved forests of Shikoku, Kyushu, and Okinawa, known for its distinctive morphology.
Key Characteristics
- ●Holoparasitic plant lacking chlorophyll (host: Fagaceae roots)
- ●Stems and leaves are vestigial; only flowers emerge above ground
- ●Flowers are bisexual with fused petals and sepals forming a tube
- ●Stamens are fused into a ring forming a cap-like (mitrate) structure
Morphological Traits
A family may include species with different trait values — multiple values indicate the range within the family.
Leaf arrangement
Alternate / Opposite / Whorled
Leaf type
Simple
Venation
Pinnate
Leaf margin
Entire
Growth form
Herb
Evergreen/Deciduous
Deciduous
Flower symmetry
Actinomorphic
Petal count
4 petals
Ovary position
Superior
Plant sex
Hermaphrodite
Phylogenetic Position
Angiosperms > Eudicots > Core Eudicots > Ericales > Mitrastemonaceae
Divergence Era
Paleogene to Neogene (ca. 30 million years ago)
Representative Genera
Related Evolution Events
- ・Acquisition of holoparasitism (complete loss of photosynthetic ability)
- ・Reduction of stems and leaves with specialization to subterranean parasitic structures
- ・Evolution of a unique pollination morphology through cap-like fusion of stamens
Plants in Mitrastemon family on this site
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