Nearly 99 million years ago, droplets of tree resin in what is now northern Myanmar trapped clusters of minuscule seeds from flowering plants. These amber fossils reveal a previously unrecognized abundance and diversity of early angiosperms, with some producing dust-like seeds akin to those of modern orchids during a pivotal burst in plant evolution, researchers report December 4 in Scientific Reports.
Angiosperms, or flowering plants, dominate the plant world today with over 260,000 species. In their early days, they underwent a rapid expansion known as radiation, especially in the mid-Cretaceous period around 99 million years ago. But details of how these plants spread and diversified have remained murky, often called an “abominable mystery” by scientists.
Myanmar amber has preserved a wealth of ancient life, from insects to flowers, in stunning three-dimensional detail. Yet tiny plant parts like seeds have often been overlooked in favor of larger, showier fossils.
That changed when researchers examined two small amber blocks from Myanmar’s Hukawng Valley. In one block, just 3 centimeters long, they found 33 tiny seeds representing 14 different shapes, or morphotypes. Most of these, 28 seeds of 11 types, were packed into a space smaller than 80 cubic millimeters, about the size of a grain of rice. The seeds ranged from 30 to 260 micrometers long, tinier than many grains of sand.
These seeds often featured a dense core attached to a wing of varying design, such as eccentric lobes or full surrounds, suggesting they were built for wind dispersal. “This dispersal strategy of angiosperms has never been heard before for angiosperms in the Mid-Cretaceous,” the researchers write.
In the second amber block, at least 66 wingless seeds were clustered in an area less than 1 square millimeter, likely from a single fruit. These showed surprising variety: most rectangular and boxy, but some rounded and elongated. This hints at flexibility in seed form from the parent plant, perhaps due to developmental differences or adaptability. At 34 to 55 micrometers long, they represent the smallest rectangular seeds known from any fossil or living plant.
All the seeds shared a key trait: their extreme smallness, far tinier than those of non-flowering plants like gymnosperms. They also lacked a tough outer coat, a feature seen in orchid seeds today. While not confirming a direct link to orchids, the fossils show early flowering plants using a similar approach to scatter lightweight “dust seeds” on the breeze.
“The present discovery reflects that, during their mid-Cretaceous radiation, at least some taxa adopted a strategy similar to that of extant orchids,” the researchers note. “If later studies may confirm the phylogenetic relationship between our fossils and orchids, the current interpretation of orchid history would need revision.”
Citations
X. Wang et al. Fossil evidence of orchid-like dust seeds in Myanmar amber featuring early angiosperm radiation. Scientific Reports. Published online December 4, 2025. DOI: 10.1038/s41598-025-27211-6
