acalycinous
adj. C2 Proficiency aca·ly·ci·nous
adj. describing a flower that does not have a calyx, which is the outer ring of petals.
adj. lacking a calyx, the outer whorl of floral organs that typically protects the flower bud.
The acalycinous flower lacks the outer layer of petals.
Botanists identified the specimen as acalycinous because the outer floral envelope was completely absent.
In some primitive flowering plants, the acalycinous condition is observed, where the sepals have not yet evolved into distinct structures to protect the reproductive organs.