Argyrochosma peninsularis

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Argyrochosma peninsularis
Baja California false cloak fern overall habit.jpg
Argyrochosma peninsularis, showing scattering of farina on upper surface of leaf.
Scientific classification OOjs UI icon edit-ltr.svg
Kingdom: Plantae
Clade: Tracheophytes
Division: Polypodiophyta
Class: Polypodiopsida
Order: Polypodiales
Family: Pteridaceae
Genus: Argyrochosma
Species:
A. peninsularis
Binomial name
Argyrochosma peninsularis
Synonyms
  • Hemionitis cairon Christenh.
  • Notholaena peninsularisMaxon & Weath.

Argyrochosma peninsularis is a fern endemic to Baja California Sur. It grows in dry, rocky places. First described as a species in 1939, it was transferred to the new genus Argyrochosma (the "false cloak ferns") in 1987, recognizing their distinctness from the "cloak ferns" ( Notholaena sensu stricto ). A dusting of powdery material and the presence of occasional scales on the central axis of its leaves help distinguish it from related species.

Contents

Description

Argyrochosma peninsularis is a medium-sized epipetric fern. The rhizome is short and compact, and may be horizontal or upright. [1] It bears linear-subulate (awl-shaped) [2] or lanceolate scales, [1] 3 to 5 millimeters (0.1 to 0.2 in) long and acuminate at the tip, with entire (toothless) margins. [1] [2] They are of a uniform color, [2] pale to chestnut brown [2] or orange-brown. [1]

Fronds arise from the rhizome in clumps; they measure 18 to 37 centimeters (7.1 to 15 in) in total length, [1] sometimes as short as 15 centimeters (5.9 in), [2] about 40% of which is made up by the stipe (the stalk of the leaf, below the blade). [1] The stipe is a glossy dark purple [1] or dark chestnut brown [2] in color, rounded, and bears scales near the base, similar to those of the rhizome but reduced in size. [1] [2]

The leaf blades are deltate (triangular) to oblong-lanceolate, [1] ovate-lanceolate or ovate. [2] They are bipinnate-pinnatifid (divided into pinnae and deeply lobed pinnules). [1] [2] The rachis (leaf axis) has sparse white farina (powder) scattered on its surface and occasional narrow scales about 1 millimeter (0.04 in) long. [1] [2] Each blade has 7 to 12 pairs of pinnae, which are widely spaced, lanceolate [2] to narrowly oblong in shape, with a short stalk at the base, or none at all, connecting them to the rachis. [1] The lowest pair of pinnae is slightly shorter than those above. [2] The ultimate segments are oblong to ovate or nearly deltate, and the dark color of their stalks usually passes into the leaf, rather than halting at a joint at the segment base. Hairs are not present on the leaf blade. The upper surface bears scattered glands and farina while the lower surface is densely covered in white farina. [1] [2]

The sori occur along the veins, starting from halfway to two-thirds of the way out from axis to edge. The edges of the leaf segments do not curl or fold to protect them. Each sporangium contains 64 spores. [1] [2] The spores are nearly smooth, unlike many members of the genus. [3]

The lack of joints at the leaf segment bases, very dark leaf and segment axes, and the presence of scales and farina on the rachis help distinguish it from other species in the genus, [4] particularly A. incana. [3]

Taxonomy

It was first described by William Ralph Maxon and Charles Alfred Weatherby in 1939 as Notholaena peninsularis, based on material collected in Baja California. The epithet presumably refers to its range being limited to the Baja California Peninsula. They placed it within a group of ferns closely related to Notholaena nivea. [5] Both Edwin Copeland and Weatherby suggested in the 1940s that this group of ferns might represent a distinct genus of its own. [6] This was finally addressed in 1987 by Michael D. Windham, who was carrying out phylogenetic studies of these genera. He elevated Notholaena sect. Argyrochosma to become the genus Argyrochosma , [7] and transferred this species to that genus as A. peninsularis. [8] In 2018, Maarten J. M. Christenhusz transferred the species to Hemionitis as H. cairon (the epithet peninsularis was preoccupied), as part of a program to consolidate the cheilanthoid ferns into that genus. The epithet refers to the centaur Cairon in the novel The Neverending Story . [9]

It lies within a subclade of the genus that also contains A. delicatula, A. incana, A. pallens, A. palmeri, and A. pilifera. All members of the clade share pale farina principally composed of terpenoid compounds, unlike the dihydrostilbenoids found in the farina of other members of the genus. [10]

Distribution and habitat

Argyrochosma delicatula is only known from the state of Baja California Sur, in Mexico. [4]

It grows in dry, rocky places, especially on granite, at an altitude of 1,200 to 2,150 meters (3,940 to 7,050 ft). [11]

Notes and references

Related Research Articles

<i>Argyrochosma</i> Genus of ferns in the family Pteridaceae

Argyrochosma is a genus of ferns known commonly as false cloak ferns. The genus is included in the Cheilanthoideae subfamily of the Pteridaceae. Species now in this genus were previously treated as members of related genera Notholaena or Pellaea but were segregated into their own genus in 1987. These ferns, of which there are about 20 species, are mostly native to the Americas, from North to South and including the Caribbean, while one species, A. connectens, is known from Sichuan, China. They are commonly found growing in cracks between rocks. Their leaves are generally shorter than 40 centimeters and have rounded bluish or grayish green segments. Often the lower surface of the segments is coated in a white dust, and the sporangia contain brown spores.

<i>Myriopteris clevelandii</i> Species of fern

Myriopteris clevelandii, formerly known as Cheilanthes clevelandii, is a species of lip fern known by the common name Cleveland's lip fern. It is native to southern California and Baja California in Mexico. The leaf is divided into small, bead-like segments densely covered with scales beneath. In M. clevelandii, some of these scales are reduced to hairlike structures, which help distinguish it from the closely related M. covillei. It is usually found growing on exposed rock, particularly igneous rock.

<i>Argyrochosma jonesii</i> Species of fern in the family Pteridaceae

Argyrochosma jonesii, known as Jones' false cloak fern, is a species of fern native to the southwestern United States and Sonora, Mexico. It grows on calcareous rocks, and has small, finely-divided leaves with a leathery texture and dark axes connecting the leaf segments. Unlike many members of Argyrochosma, it does not secrete white powder on the underside of its leaves. First described as a species in 1917, it was transferred to the new genus Argyrochosma in 1987, recognizing their distinctness from the "cloak ferns".

<i>Argyrochosma nivea</i> Species of fern in the family Pteridaceae

Argyrochosma nivea is an Andean fern species in the genus Argyrochosma.

Myriopteris aemula, the Texas lip fern or rival lip fern, is a moderately-sized fern of Texas and Mexico, a member of the family Pteridaceae. Unlike many members of its genus, its leaves have a few hairs on upper and lower surfaces, or lack them entirely. One of the cheilanthoid ferns, it was usually classified in the genus Cheilanthes as Cheilanthes aemula until 2013, when the genus Myriopteris was again recognized as separate from Cheilanthes. It typically grows on limestone rock.

<i>Argyrochosma dealbata</i> Species of fern in the family Pteridaceae

Argyrochosma dealbata, the powdery false cloak fern, is a small fern endemic to the central and southern United States. It grows on calcareous rocks, such as limestone. Its leaves are highly divided, with leaf segments joined by shiny, chestnut-brown axes, and their undersides are coated with white powder, giving the fern its name. First described as a species in 1814, it was transferred to the new genus Argyrochosma in 1987, recognizing their distinctness from the "cloak ferns".

Argyrochosma connectens is a small cheilanthoid fern endemic to Sichuan, China. It is the only member of its genus known from Asia. Relatively rare, it is found growing in the crevices of limestone rocks in hot, dry valleys. The species was long classified in the genus Pellaea, but after a phylogenetic study in 2015 was transferred to Argyrochosma.

Argyrochosma delicatula is a fern known from northeastern Mexico. It grows in rocky habitats, either in sun or in shade, and is distinguished from similar species by the presence of pale yellow powder on the underside of its leaves. First described as a species in 1939, it was transferred to the new genus Argyrochosma in 1987, recognizing their distinctness from the "cloak ferns".

Argyrochosma pallens is a fern endemic to Mexico. It has narrow, divided leaves with brown axes; the leaves are dusted with white powder above and coated in it below. First described as a species in 1956, it was transferred to the new genus Argyrochosma in 1987, recognizing their distinctness from the "cloak ferns".

Argyrochosma chilensis is a fern endemic to the Juan Fernández Islands off the coast of Chile. It has leathery, thrice-divided leaves with dark brown axes; the leaves are coated with white powder below. First described as a species in 1853, it was transferred to the new genus Argyrochosma in 1987, recognizing their distinctness from the "cloak ferns".

Argyrochosma stuebeliana is a fern endemic to Peru. Its highly divided, leathery leaves are coated with white powder on their under surface. Originally described as a variety of Argyrochosma dealbata in 1909, based on a single leaf collected by Alphons Stübel, whom its name honors, it was recognized as a distinct species in 1961, distinguished from similar members of the genus largely by its round leaf segments. It was transferred to the new genus Argyrochosma in 1987, recognizing their distinctness from the "cloak ferns".

<i>Myriopteris aurea</i> Species of fern

Myriopteris aurea, the golden lip fern or Bonaire lip fern, is a moderately-sized fern native to the Americas, a member of the family Pteridaceae. Unlike many members of its genus, its leaf is only modestly dissected into lobed leaflets (pinnae), which are hairy both above and below. One of the cheilanthoid ferns, until 2013 it was classified in the genus Cheilanthes as Cheilanthes bonariensis, when the genus Myriopteris was again recognized as separate from Cheilanthes. It typically grows on dry, rocky slopes, and ranges from Mexico, where it is common and widespread, and the southwestern United States south and east through Central and South America as far as Chile and Argentina.

Argyrochosma lumholtzii is a rare fern in the family Pteridaceae known from Sonora, Mexico. It is quite similar to Jones' false cloak fern, but has black leaf axes and a less highly divided leaf. First described as a species in 1939, honoring the explorer Carl Sofus Lumholtz, it was transferred to the new genus Argyrochosma in 1987, recognizing their distinctness from the "cloak ferns".

<i>Argyrochosma fendleri</i> Species of fern in the family Pteridaceae

Argyrochosma fendleri, Fendler's false cloak fern, is a fern known from the western United States and northwestern Mexico. It grows in rocky habitats, and is distinguished from other members of the genus by its zig-zag leaf axes. Like many species in the genus, it bears white powder on the underside of its leaves. First described as a species in 1851, it was transferred to the new genus Argyrochosma in 1987, recognizing their distinctness from the "cloak ferns".

Argyrochosma incana, the hairy false cloak fern, is a fern known from the southwestern United States through Mexico to Guatemala, and from a disjunct population in the Dominican Republic. It grows on rocky slopes and steep banks, often in forests. Like many of the false cloak ferns, it bears white powder on the underside of its leaves. First described as a species in 1825, it was transferred to the new genus Argyrochosma in 1987, recognizing their distinctness from the "cloak ferns".

Argyrochosma palmeri is a fern endemic to Mexico. It has narrow, divided leaves with black axes; the leaves are coated in white powder below, and sparsely dusted or free of it above. First described as a species in 1887, it was transferred to the new genus Argyrochosma in 1987, recognizing their distinctness from the "cloak ferns".

Argyrochosma pilifera is a fern endemic to Mexico. It has lance-shaped, divided leaves with dark purple axes; the undersides of the leaves are coated in white powder. First described as a species in 1956, it was transferred to the new genus Argyrochosma in 1987, recognizing their distinctness from the "cloak ferns".

<i>Argyrochosma formosa</i> Species of fern in the family Pteridaceae

Argyrochosma formosa is a fern known from eastern and central Mexico and Guatemala. It grows on rocky slopes, particularly on limestone. Unlike many members of the genus, it lacks white powder on the underside of its leaves. First described as a species in 1842, it was transferred to the new genus Argyrochosma in 1987, recognizing their distinctness from the "cloak ferns".

<i>Argyrochosma limitanea</i> Species of fern in the family Pteridaceae

Argyrochosma limitanea, the southwestern false cloak fern, is a species of fern native to the southwestern United States and Sonora, Mexico. It grows on calcareous rocks, and has small, finely-divided leaves with a leathery texture, dark axes connecting the leaf segments, and a heavy coating of white powder on the undersurface. It reproduces apogamously; two subspecies are recognized, which may have originated independently through the hybridization of other taxa not yet discovered. First described as a species in 1919, it was transferred to the new genus Argyrochosma in 1987, recognizing their distinctness from the "cloak ferns".

<i>Argyrochosma microphylla</i> Species of fern in the family Pteridaceae

Argyrochosma microphylla, the small-leaf false cloak fern, is a species of fern native to New Mexico, Texas and northern Mexico. It grows on limestone rocks and cliffs, and has finely-divided leaves with small leaf segments, often folded in half when dry, which lack the white powder present on the leaf underside of many related species. First described as a species in 1869, it was transferred to the new genus Argyrochosma in 1987, recognizing their distinctness from the "cloak ferns".

References

  1. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 Mickel & Smith 2004, p. 70.
  2. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 Tryon & Weatherby 1956, p. 83.
  3. 1 2 Maxon & Weatherby 1939, p. 16.
  4. 1 2 Mickel & Smith 2004, p. 71.
  5. ↑ Maxon & Weatherby 1939, pp. 15–16.
  6. ↑ Windham 1987, p. 37.
  7. ↑ Windham 1987, p. 38.
  8. ↑ Windham 1987, p. 40.
  9. ↑ Christenhusz, Fay & Byng 2018, p. 11.
  10. ↑ Sigel et al. 2011, p. 561.
  11. ↑ Mickel & Smith 2004, p. 65.

Works cited

  • Christenhusz, Maarten J. M.; Fay, Michael F.; Byng, James W. (2018). Plant Gateway's the Global Flora: A practical flora to vascular plant species of the world. Vol. 4. ISBN   978-0-9929993-9-1.
  • Maxon, W. R.; Weatherby, C. A. (1939). "Some species of Notholaena, new and old". Contributions from the Gray Herbarium. 127. JSTOR   41764097.
  • Mickel, John T.; Smith, Alan R. (2004). The Pteridophytes of Mexico. Memoirs of the New York Botanical Garden. Vol. 88. Bronx, New York: New York Botanical Garden. ISBN   978-0-89327-488-7.
  • Tryon, Rolla M.; Weatherby, Una F. (1956). "A revision of the American species of Notholaena". Contributions from the Gray Herbarium of Harvard University (179): 1–106. JSTOR   41764632.
  • Sigel, Erin M.; Windham, Michael D.; Huiet, Layne; Yatskievych, George; Pryer, Kathleen M. (2011). "Species Relationships and Farina Evolution in the Cheilanthoid Fern Genus Argyrochosma (Pteridaceae)". Systematic Botany. 36 (3): 554–564. doi:10.1600/036364411X583547. JSTOR   23028975.
  • Windham, Michael D. (1987). "Argyrochosma, a new genus of cheilanthoid ferns". American Fern Journal. 77 (2): 37–41. doi:10.2307/1547438. JSTOR   1547438.
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