''Aspidotis'' is a small genus of leptosporangiate

fern The ferns (Polypodiopsida or Polypodiophyta) are a group of vascular plants (plants with xylem and phloem) that reproduce via spores and have neither seeds nor flowers. They differ from mosses by being vascular, i.e., having specialized tissue ...

s known commonly as laceferns. Most species are native to slopes, ridges, and rocky outcroppings, primarily in California and Mexico, although one species included in the genus by some authorities is widely distributed in eastern Africa.

Description

Members of ''Aspidotis'' are small ferns, with shiny, tufted fronds generally less than 35 centimeters long (although ''A. schimperi'' may be larger). Fertile leaves have false indusia formed by the leaves' inrolled margins, which partially conceal the spore-bearing sori.

Taxonomy

The taxonomy of laceferns has been considerably refined since they were first described in the late 1800s. Species currently placed in ''Aspidotis'' were originally assigned to a section of '' Hypolepis'', then to '' Cheilanthes''. David Lellinger established ''Aspidotis'' as a distinct genus based on characteristic features of its false indusia and its leaves, including their shiny surface, although as late as the 1990 publication of the Kubitzki system, these ferns were sometimes still included in ''Cheilanthes''.

Species

, the ''Checklist of Ferns and Lycophytes of the World'' recognized five species, including one identified as a fertile interspecific hybrid. *'' Aspidotis californica'' (Nutt. ex Hook.) Nutt. ex Copel. – California lacefern *'' Aspidotis carlotta-halliae'' (Wagner & E. F. Gilbert) Lellinger – Carlotta Hall's lacefern or tufted lacefern, a fertile hybrid of ''A. californica'' and ''A. densa'',

endemic Endemism is the state of a species being found only in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also foun ...

to California *'' Aspidotis densa'' (Brack.) Lellinger – cliffbrake or Indian's dream *'' Aspidotis meifolia'' (D.C.Eaton) Pic.Serm. – endemic to Mexico *'' Aspidotis schimperi'' (Kunze) Pic. Serm. – the African species Other species of plants commonly known as laceferns are not part of ''Aspidotis'' and are often not closely related. '' Microlepia strigosa'' is from a different order of ferns, and '' Asparagus setaceus'' is not a fern at all.

Ecology

Ferns in this genus grow in a variety of conditions, from low woodland slopes, to chaparral, to higher-elevation ridges, to marginal habitats like rocky crevices and the bases of boulders. Some laceferns show an affinity for serpentine soil. In particular, disjunct populations of ''A. densa'' in eastern North America are edaphic endemics. ''A. carlotta-halliae'' and the West Coast populations of ''A. densa'' are commonly associated with these ultramafic soils but are not restricted to them.

Etymology

Not all authorities agree on the exact etymology of ''Aspidotis''. In all cases, the name is derived from Greek, and refers to the distinctive shield-like false indusium found especially in ''A. californica''. Some authors suggest ασπιδοτες (shield-bearer) as the intended origin, while others claim ασπιδος-ωτος (shield-eared).

References

{{Taxonbar, from=Q2290670 Pteridaceae Fern genera