Cheilanthes

Cheilanthes, commonly known as lip ferns, is a genus of about 180 species of rock-dwelling ferns with a cosmopolitan distribution in warm, dry, rocky regions, often growing in small crevices high up on cliffs. Most are small, sturdy and evergreen. The leaves, often densely covered in trichomes, spring directly from the rootstocks. Many of them are desert ferns, curling up during dry times and reviving with the coming of moisture. At the ends of veins sporangia, or spore-bearing structures, are protected by leaf margins, which curl over them.
Taxonomy
The genus name is derived from the Greek words χεῖλος (cheilos), meaning "lip," and ἄνθος (anthos), meaning "flower."
Cheilanthes as traditionally circumscribed is now known to be highly paraphyletic, comprising at least four generically separate groups. The type species, C. micropteris, is most closely allied to the genera Aleuritopteris and Sinopteris (Schuettpelz et al.). In the early 21st century, many species, principally from the New World, were moved into the new genus Gaga and the revived genus Myriopteris. Further work remains to be done to render Cheilanthes monophyletic. Members of many other cheilanthoid genera have at times been given names in the genus.
Species
The circumscription of the genus was uncertain . The Checklist of Ferns and Lycophytes of the World lists species in several distinct groups.
Cheilanthes sensu stricto contains about 20 species from North and tropical Central and South America:
Cheilanthes arequipensis (Maxon) R.M.Tryon & A.F.Tryon
Cheilanthes fractifera Tryon
Cheilanthes glutinosa M.Kessler & A.R.Sm.
Cheilanthes incarum Maxon
Cheilanthes incisa Kunze ex Mett.
Cheilanthes juergensii Rosenst.
Cheilanthes laciniata Sodiro
Cheilanthes leonardii Maxon
Cheilanthes leucopoda Link
Cheilanthes lonchophylla (R.M.Tryon) R.M.Tryon & A.F.Tryon
Cheilanthes macleanii (J.Sm.) Hook.
Cheilanthes mathewsii Kunze
Cheilanthes micropteris Sw.
Cheilanthes pantanalensis E.L.M.Assis, Ponce & Labiak
Cheilanthes peruviana (Desv.) Moore
Cheilanthes poeppigiana Mett. ex Kuhn
Cheilanthes rufopunctata Rosenst.
Cheilanthes sarmientoi Ponce
Cheilanthes spiculata Mickel
Cheilanthes squamosa Gill. ex Hook. & Grev.
Cheilanthes volcanensis de la Sota
Cheilanthes sensu lato contains about 50 species that molecular phylogenetic studies suggest do not form a clade with the core Cheilanthes species, falling into separate clades, but for which no placement outside Cheilanthes was available :
Cheilanthes adiantoides T.C.Chambers & P.A.Farrant
Cheilanthes angustifrondosa Alston
Cheilanthes austrotenuifolia H.M.Quirk & T.C.Chambers
Cheilanthes bergiana Schltdl.
Cheilanthes boivinii Mett. ex Kuhn
Cheilanthes bolborrhiza Mickel & Beitel
Cheilanthes bonapartei J.P.Roux
Cheilanthes botswanae Schelpe & N.C.Anthony
Cheilanthes brownii (Desv.) Domin
Cheilanthes buchananii (Baker) Domin
Cheilanthes capensis (Thunb.) Sw.
Cheilanthes caudata R.Br.
Cheilanthes ceterachoides A.W.Klopper & Klopper
Cheilanthes contracta Kunze
Cheilanthes deboeri Verdc.
Cheilanthes deltoidea Kunze
Cheilanthes depauperata Baker
Cheilanthes dinteri Brause
Cheilanthes distans (R.Br.) Mett.
Cheilanthes dolomiticola (Schelpe) Schelpe & N.C.Anthony
Cheilanthes eckloniana (Kunze) Mett.
Cheilanthes erythraea Pic. Serm.
Cheilanthes fragillima F.Muell.
Cheilanthes hastata (L. fil.) Kunze
Cheilanthes hirta Sw.
Cheilanthes inaequalis (Kunze) Mett.
Cheilanthes induta Kunze
Cheilanthes involuta (Sw.) Schelpe & N.C.Anthony
Cheilanthes kunzei Mett.
Cheilanthes lasiophylla Pic. Serm.
Cheilanthes leachii (Schelpe) Schelpe
Cheilanthes lozanoi (Maxon) R.M.Tryon & A.F.Tryon
Cheilanthes madagascariensis Baker
Cheilanthes marlothii (Hieron.) Schelpe
Cheilanthes muelleri (Hook.) comb. ined.
Cheilanthes multifida (Sw.) Sw.
Cheilanthes namaquensis (Baker) Schelpe & N.C.Anthony
Cheilanthes nielsii W.Jacobsen
Cheilanthes nitida (R.Br.) P.S.Green
Cheilanthes parviloba (Sw.) Sw.
Cheilanthes pentagona Schelpe & N.C.Anthony
Cheilanthes perlanata (Pic. Serm.) Kornas
Cheilanthes perrieri J.P.Roux
Cheilanthes praetermissa D.L.Jones
Cheilanthes prenticei Luerss.
Cheilanthes pumilio (R.Br.) F.Muell.
Cheilanthes quadripinnata (Forsk.) Kuhn
Cheilanthes reynoldsii (F.Muell.) comb. ined.
Cheilanthes robusta (Kunze) Tryon
Cheilanthes sieberi Kunze
Cheilanthes similis Ballard
Cheilanthes skinneri (Hook.) R.M.Tryon & A.F.Tryon
References
Flora Europaea: Cheilanthes
Flora of North America: Cheilanthes
Cheilanthes glauca pictures from Chilebosque.
"lip fern." Encyclopædia Britannica Online. 30 Nov 2007.
Fern genera
Taxa named by Olof Swartz