Argyrochosma microphylla

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Argyrochosma microphylla
Argyrochosma microphylla in crevice.jpg
Argyrochosma microphylla growing in a rocky crevice
Status TNC G4.svg
Apparently Secure  (NatureServe) [1]
Scientific classification OOjs UI icon edit-ltr.svg
Kingdom: Plantae
Clade: Tracheophytes
Division: Polypodiophyta
Class: Polypodiopsida
Order: Polypodiales
Family: Pteridaceae
Genus: Argyrochosma
Species:
A. microphylla
Binomial name
Argyrochosma microphylla
Synonyms
  • Cheilanthes parvifolia(R.M.Tryon) Mickel
  • Hemionitis vooshvazool Christenh.
  • Notholaena parvifoliaR.M.Tryon
  • Pellaea microphyllaMett. ex Kuhn
  • Pellaea pulchella var. microphylla(Mett. ex Kuhn) Baker

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 (the "false cloak ferns") in 1987, recognizing their distinctness from the "cloak ferns" ( Notholaena sensu stricto ).

Contents

Description

The rhizome is short and horizontal, with leaves closely spaced. [2] [3] It bears thin, [2] narrowly lanceolate [4] or linear [2] brown to dark orange, [3] chestnut-brown, [2] or reddish-brown scales [4] 4 to 7 millimeters (0.2 to 0.3 in), [3] of a uniform color and with entire (toothless) margins. [2] [4]

The leaves are 7 to 25 centimeters (2.8 to 9.8 in) long, arising in clumps. [3] [5] The stipe (the stalk of the leaf, below the blade) is rounded, somewhat flattened [3] or grooved on the upper surface, [2] [5] reddish-brown to dark brown, [4] or chestnut brown, [3] usually darker at the base, [2] without hairs or scales [3] except for a few scales like those of the rhizome at the very base. [2] It is 3 to 12 centimeters (1.2 to 4.7 in) long [4] and 0.75 to 1.5 millimeters (0.030 to 0.059 in) in diameter, [5] making up about one-half to one-third of the total length of the leaf. [3]

The leaf blades are 5 to 14 centimeters (2.0 to 5.5 in) long and 2 to 7 centimeters (0.8 to 3 in) wide. [4] They vary from deltate (triangular) to ovate in shape, [3] [5] and range from tripinnate (cut into pinnae, pinnules and pinnulets) to quadripinnate at the base, where the leaf blade is most divided; [3] [5] it becomes merely bipinnate near the tip. [2] The leaf blade is truncate (abruptly terminating), at the base and is acute (pointed) to acuminate at the tip. [4] The rachis (leaf axis) is flattened or shallowly grooved above, straight or somewhat zig-zagging, and dark in color (though lighter than the stipe), [2] as are the axes of the leaf segments. The color stops abruptly at a joint at the base of the leaf segment. [3] [5] There are 5 to 9 pairs of pinnae, alternating along the rachis or nearly opposite, and abruptly contracting in width near the tip. [2] The costae (pinna axes) are straight to somewhat zig-zagging; when the latter, they typically do not branch at the angles. [5] Leaf segments are orbicular (circular) to cordate (heart-shaped). [3] They appear narrow or triangular when dry and curled, [4] and are borne on small stalks. [2] The leaf tissue is gray-green and leathery, obscuring the veins from the upper surface, and does not bear hairs or scales on either surface. Unlike many species in the genus, farina (powder) is not present on either surface of the leaf, [3] [5] [4] although both surfaces are glaucous. [2]

In fertile leaf segments, the sporangia are close to the margin, borne along the further third of the secondary veins branching from the midrib of the segment. [3] [5] They form a band about 1 millimeter (0.04 in) wide along the edge of each segment. [3] Each sporangium contains 64 spores. The leaf segments are bent or curled under, often concealing the sporangia. [2] [3] [5] The curled tissue retains the same texture as the rest of the leaf, and is not modified into a false indusium. Fertile segments often fold along their long axis. [3] A. microphylla is a sexual diploid, with a chromosome count of 2n = 54. [3] [5]

Underside of a leaf, showing the lack of farina and slightly zig-zag axes. Argyrochosma microphylla leaf underside.jpg
Underside of a leaf, showing the lack of farina and slightly zig-zag axes.

The small leaf segments and shallow groove on the rachis make A. microphylla distinct from other species in the genus. The zig-zag character of the rachis in some specimens resembles A. fendleri , but the latter bears farina, and the smaller axes zig-zag as well. [3] Of the other North American taxa lacking farina, A. formosa has somewhat larger leaf segments and a dark, straight rachis without a groove, while A. jonesii and A. lumholtzii lack the distinct joint at the base of the leaf, and do not have dramatically folded leaf segments when dry. [6]

Taxonomy

The species was first described in 1869 as Pellaea microphylla by Max Kuhn, who was presenting material the herbarium left behind by the late Georg Heinrich Mettenius. He used Mettenius' name for the species, which had been collected in New Mexico by Charles Wright in 1849 and had heretofore been lumped with P. pulchella . The rationale for the epithet microphylla, meaning "small-leaved", was not given. [7] Hooker & Baker, in their second edition of Synopsis Filicum (1874), treated it as P. pulchella var. microphylla. [8]

Rolla M. Tryon Jr., when finishing Charles Alfred Weatherby's revision of American Notholaena, transferred the species there under the replacement name of N. parvifolia, the name N. microphylla being preoccupied. [2] He chose the epithet parvifolia, which also means "small-leaved", to reflect the meaning of the original epithet. [9] While Tryon considered it impossible to reasonably subdivide Notholaena into sections based on the data available at the time, [10] both Edwin Copeland and Weatherby himself had suggested in the 1940s that a group of ferns related to N. nivea might represent a distinct genus. [11] John T. Mickel, following Copeland's opinion that Notholaena was best lumped into a broadly defined Cheilanthes , transferred the species there as C. parviflora in 1979. [12]

The recognition of the N. nivea group as a genus 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 , [13] and transferred this species to that genus as A. microphylla. [14] In 2018, Maarten J. M. Christenhusz transferred the species to Hemionitis as H. vooshvazool , as part of a program to consolidate the cheilanthoid ferns into that genus. The epithet refers to the nighthob messenger Vooshvazool in the novel The Neverending Story . [15]

Phylogenetic studies have shown that A. microphylla is a sister species to A. formosa ; these two species form a clade sister to another clade containing A. jonesii and A. lumholtzii. [16] All four species lack farina, and their common ancestor is hypothesized to have diverged from the ancestor of the rest of the genus before farina production developed in the latter. [17]

Distribution and habitat

Argyrochosma microphylla is known in the United States from southeastern New Mexico and Trans-Pecos Texas, with outlying stations as far as Brazos County, Texas and Bernalillo County, New Mexico. [18] In Mexico, it ranges across the northern states from Sonora to Nuevo León and south into Zacatecas. [3]

It grows on rocky limestone hillsides and cliffs and talus slopes, at altitudes from 300 to 2,100 meters (980 to 6,900 ft). [5] [3]

Cultivation

It prefers high light, and moist-dry, well-drained garden soil with sand, perhaps of high pH. [19]

Notes and references

Related Research Articles

<i>Notholaena</i> Genus of ferns

Notholaena, cloak fern, is a genus of ferns in the Cheilanthoideae subfamily of the Pteridaceae. Ferns of this genus are mostly epipetric or occurring in coarse, gravelly soils, and are most abundant and diverse in the mountain ranges of warm arid or semiarid regions. They typically have a creeping or erect rhizome and leaves that are pinnatifid to pinnate-pinnatifid with marginal sori protected by a false indusium formed from the reflexed margin of the leaf. Members of Notholaena also have a coating of whitish or yellowish farina on the surfaces of the leaves. The farina is often limited to the abaxial (lower) leaf surface, but may occur on the adaxial (upper) leaf surface as well. Members of the related Pentagramma genus have a similar lower leaf-surface farina.

<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 cm (16 in) 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>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.

<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".

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

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 in 1987, recognizing their distinctness from the "cloak ferns". A dusting of powdery material and the presence of occasional scales on the central axis of its leaves help distinguish it from related species.

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>Myriopteris rufa</i> Species of fern

Myriopteris rufa, commonly known as Eaton's lip fern, is a moderately-sized fern of Mexico and the southwestern United States, with outlying populations in Costa Rica and the Appalachian Mountains. One of the cheilanthoid ferns, it was usually classified in the genus Cheilanthes, as Cheilanthes eatonii, until 2013, when the genus Myriopteris was again recognized as separate from Cheilanthes. It typically grows in rocky habitats, most frequently on limestone but also sometimes on basalt or shale.

References

  1. ↑ NatureServe 2020.
  2. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 Tryon & Weatherby 1956, p. 98.
  3. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 Mickel & Smith 2004, p. 69.
  4. 1 2 3 4 5 6 7 8 9 Lellinger 1985, p. 153.
  5. 1 2 3 4 5 6 7 8 9 10 11 12 Windham 1993.
  6. ↑ Mickel & Smith 2004, p. 64.
  7. ↑ Kuhn 1869, p. 86.
  8. ↑ Hooker & Baker 1874, p. 477.
  9. ↑ Tryon & Weatherby 1956, p. 99.
  10. ↑ Tryon & Weatherby 1956, p. 6.
  11. ↑ Windham 1987, p. 37.
  12. ↑ Mickel 1979, p. 435.
  13. ↑ Windham 1987, p. 38.
  14. ↑ Windham 1987, p. 40.
  15. ↑ Christenhusz, Fay & Byng 2018, p. 23.
  16. ↑ Sigel et al. 2011, p. 558.
  17. ↑ Sigel et al. 2011, p. 559.
  18. ↑ Kartesz 2014.
  19. ↑ Hoshizaki & Moran 2001, p. 190.

Works cited

  • Christenhusz, Maarten J. M.; Fay, Michael F.; Byng, James W. (8 February 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.
  • Hooker, William; Baker, John Gilbert (1874). Synopsis Filicum. Vol. copy 1 (2nd ed.). London: Robert Hardwicke.
  • Hoshizaki, Barbara Joe; Moran, Robbin C. (2001). Fern Grower's Manual. Portland, Oregon: Timber Press. ISBN   9780881924954.
  • Kartesz, John T. (2014). "Argyrochosma". Biota of North America Program.
  • Kuhn, Maximiliano (1869). "Reliquieae Mettenianae". Linnaea. 36 (1): 41–169.
  • Lellinger, David B. (1985). A Field Manual of the Ferns & Fern-Allies of the United States & Canada . Washington, DC: Smithsonian Institution Press. ISBN   0874746035.
  • Mickel, John T. (1979). "The fern genus Cheilanthes in the continental United States". Phytologia. 41 (6): 431–437. doi: 10.5962/bhl.part.20791 .
  • 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.
  • "Argyrochosma microphylla". NatureServe. November 10, 2020.
  • 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. S2CID   16214744.
  • 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. doi: 10.5962/p.336378 . JSTOR   41764632.
  • Windham, Michael D. (1987). "Argyrochosma, a new genus of cheilanthoid ferns". American Fern Journal. 77 (2): 37–41. doi:10.2307/1547438. JSTOR   1547438.
  • Windham, Michael D. (1993). "Argyrochosma microphylla". In Flora of North America Editorial Committee (ed.). Flora of North America North of Mexico. Vol. 2: Pteridophytes and Gymnosperms. New York and Oxford: Oxford University Press.
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