''Aspidotis'' is a small genus of
leptosporangiate fern
A fern (Polypodiopsida or Polypodiophyta ) is a member of a group of vascular plants (plants with xylem and phloem) that reproduce via spores and have neither seeds nor flowers. The polypodiophytes include all living pteridophytes except t ...
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
A frond is a large, divided leaf. In both common usage and botanical nomenclature, the leaves of ferns are referred to as fronds and some botanists restrict the term to this group. Other botanists allow the term frond to also apply to the lar ...
generally less than 35 centimeters long (although ''A. schimperi'' may be larger
). Fertile leaves have false
indusia
A sorus (pl. sori) is a cluster of sporangia (structures producing and containing spores) in ferns and fungi. A coenosorus (plural coenosori) is a compound sorus composed of multiple, fused sori.
Etymology
This New Latin word is from Ancient Gr ...
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
Section, Sectioning or Sectioned may refer to:
Arts, entertainment and media
* Section (music), a complete, but not independent, musical idea
* Section (typography), a subdivision, especially of a chapter, in books and documents
** Section sign ...
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 The Kubitzki system is a system of plant taxonomy devised by Klaus Kubitzki, and is the product of an ongoing survey of vascular plants, entitled ''The Families and Genera of Vascular Plants'', and extending to 15 volumes in 2018. The survey, in th ...
, 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
In biology, a hybrid is the offspring resulting from combining the qualities of two organisms of different breeds, varieties, species or genera through sexual reproduction. Hybrids are not always intermediates between their parents (such as in ...
.
*'' 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 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 found elsew ...
to California
*''Aspidotis densa
''Aspidotis densa'' is a species of fern in the Cheilanthoid subfamily, known by the common name Indian's dream or Serpentine fern or dense lace fern. It is native to the west coast of North America from British Columbia to California and east t ...
'' (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
Order, ORDER or Orders may refer to:
* Categorization, the process in which ideas and objects are recognized, differentiated, and understood
* Heterarchy, a system of organization wherein the elements have the potential to be ranked a number of d ...
of ferns, and ''Asparagus setaceus
''Asparagus setaceus'', commonly known as common asparagus fern, asparagus grass, lace fern, climbing asparagus, or ferny asparagus, is a climbing plant in the genus ''Asparagus''. Despite its common name, the plant is not a true fern, but has le ...
'' is not a fern at all.
Ecology
Ferns in this genus grow in a variety of conditions, from low woodland slopes,chaparral
Chaparral ( ) is a shrubland plant community and geographical feature found primarily in the U.S. state of California, in southern Oregon, and in the northern portion of the Baja California Peninsula in Mexico. It is shaped by a Mediterranean c ...
, to higher-elevation ridges, to marginal habitats like rocky crevices and the bases of boulders.serpentine soil
Serpentine soil is an uncommon soil type produced by weathered ultramafic rock such as peridotite and its metamorphic derivatives such as serpentinite. More precisely, serpentine soil contains minerals of the serpentine subgroup, especially anti ...
. 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
Ultramafic rocks (also referred to as ultrabasic rocks, although the terms are not wholly equivalent) are igneous and meta-igneous rocks with a very low silica content (less than 45%), generally >18% MgO, high FeO, low potassium, and are composed ...
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
Greek may refer to:
Greece
Anything of, from, or related to Greece, a country in Southern Europe:
*Greeks, an ethnic group.
*Greek language, a branch of the Indo-European language family.
**Proto-Greek language, the assumed last common ancestor ...
, and refers to the distinctive shield-like false indusium found especially in ''A. californica''. Some authors suggest ασπιδοτες (shield-bearer)
References
{{Taxonbar, from=Q2290670
Pteridaceae
Fern genera