Cheilanthes, commonly known as lip ferns, is a genus of ferns in the family Pteridaceae comprising roughly 180 species in the broad traditional sense, though current molecular work has reduced the core genus to around 31 accepted species. These ferns are adapted to warm, dry, rocky environments worldwide, frequently colonising small crevices on cliff faces and outcrops across every continent except Antarctica.
Most lip ferns are small, sturdy, and evergreen. Their fronds spring directly from wiry rootstocks and are often densely clothed in scales or hair-like trichomes that reduce water loss. A hallmark adaptation is their ability to curl tightly during drought and revive fully when moisture returns, a trait shared with other so-called "resurrection ferns." Spore-bearing structures (sporangia) form at or near the tips of frond veins and are protected by the rolled or reflexed leaf margins — the false indusia that inspired both the genus name and the common name.
Taxonomically, Cheilanthes has undergone major revision since the early 2000s. Molecular phylogenetic studies revealed the genus as broadly paraphyletic — a collection of at least four distinct evolutionary lineages. As a result, many New World species were transferred to the newly erected genus Gaga and the revived genus Myriopteris. The type species, Cheilanthes micropteris, is most closely allied to Aleuritopteris and Sinopteris. Core Cheilanthes species sensu stricto are distinguished by producing 32 spores per sporangium rather than the 64 typical of related genera.
Etymology
The genus name Cheilanthes derives from the Greek words χεῖλος (cheilos, meaning "lip") and ἄνθος (anthos, meaning "flower"). This refers to the distinctive lip-like false indusia — the reflexed leaf margins that curl over and protect the sporangia. The same feature gives rise to the common name "lip fern."
Distribution
Lip ferns have a cosmopolitan distribution, occurring across warm and dry regions on every inhabited continent. They are particularly characteristic of rocky habitats — cliff faces, rock outcrops, and dry canyon walls — in subtropical and warm-temperate zones of Africa, the Americas, Asia, and Australia.
Ecology
Cheilanthes species are specialist rock-dwellers (lithophytes), typically occupying small crevices in exposed cliffs and rock faces in arid to semi-arid environments. Many species are functionally poikilohydric: their fronds desiccate and curl during drought, then rehydrate and resume photosynthesis when moisture returns. Dense trichome (hair or scale) cover on fronds helps reflect solar radiation and reduce water loss, allowing survival in habitats too hot and dry for most ferns.
Taxonomy Notes
Cheilanthes as traditionally circumscribed is now understood to be highly paraphyletic, comprising at least four generically separate evolutionary groups. In the early 21st century, many species — principally from the New World — were transferred to the newly described genus Gaga and the revived genus Myriopteris. The type species, C. micropteris, is most closely related to Aleuritopteris and Sinopteris. As of October 2025, the Checklist of Ferns and Lycophytes of the World recognises 31 species in the core Cheilanthes clade; additional species remain provisionally placed in the genus pending further phylogenetic resolution. Core Cheilanthes sensu stricto are united by producing 32 (rather than 64) spores per sporangium in sexual taxa.
