Myriopteris allosuroides

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Myriopteris allosuroides
Scientific classification OOjs UI icon edit-ltr.svg
Kingdom: Plantae
Clade: Tracheophytes
Division: Polypodiophyta
Class: Polypodiopsida
Order: Polypodiales
Family: Pteridaceae
Genus: Myriopteris
Species:
M. allosuroides
Binomial name
Myriopteris allosuroides
(Mett.) Grusz & Windham
Synonyms
  • Allosorus pallidus(Baker) Kuntze
  • Cassebeera arsenei(Christ) Farw.
  • Cheilanthes allosuroidesMett.
  • Cheilosoria allosuroides(Mett.) Trevis.
  • Hemionitis allosuroides(Mett.) Christenh.
  • Hemionitis pallida(Baker) Christenh.
  • Pellaea allosuroides(Mett.) Hieron.
  • Pellaea arsenei Christ
  • Pellaea pallidaBaker

Myriopteris allosuroides is a moderately-sized fern of Mexico, a member of the family Pteridaceae. Unlike many members of its genus, its rachides are grooved on the upper surface and largely free of hairs or scales. One of the cheilanthoid ferns, it was usually classified in the genera Cheilanthes or Pellaea until 2013, when the genus Myriopteris was again recognized as separate from Cheilanthes. It typically grows on dry, rocky slopes over acidic, particularly basaltic, rock.

Contents

Description

Leaf bases are closely spaced along the rhizome, [1] which is 2 to 3 millimeters (0.08 to 0.1 in) in diameter. [2] The rhizome bears scales, which are linear with entire (untoothed) margins. [2] They are of a uniform orange-brown color, and measure 3 to 4 millimeters (0.1 to 0.2 in) long. [2]

The fronds spring up in clusters; [2] they do not unfold as fiddleheads like typical ferns (noncircinate vernation). [3] When mature, they are up to 30 centimeters (12 in) long. [2] The stipe (the stalk of the leaf, below the blade) represents about one-third of the total length of the leaf. [2] The upper surface of the stipe is grooved, [2] continuing into the rachis (leaf axis), [1] and it is shiny, dark chestnut brown to purplish brown in color. [2] It bears a few hairs, 2 millimeters (0.08 in) long and pressed against the stipe. [2] In older fronds, a line marking a joint can be seen near the base of the stipe; when leaves die and fall off, they leave behind 1 to 1.5 centimeters (0.39 to 0.59 in) of the stipe below the joint. [2]

The leaf blades are lanceolate, bipinnate (cut into pinnae and pinnules) to tripinnate (cut into pinnae, pinnules, and pinnulets). The leaf tissue is firm in texture. [2] The rachis lacks hairs and scales, except for a few linear, tan scales at the bases of pinnae. From 8 to 13 pairs of pinnae are present; their lobes or pinnulets are largely elliptical or lance-shaped, often bearing auricles. [2] The upper surface of the pinnae lacks hairs and scales, and is dotted with very small papillae. The underside is also free of hairs and scales, except for a few long hairs on the costae (pinna axes). [2]

On fertile fronds, the sori are protected by false indusia formed by the edge of the leaf curling back over the underside. The recurved edges are firm and distinctly curved, somewhat modified in comparison to the rest of the leaf tissue, and become thin only at the edge, which is very slightly erose (ragged). The sori are long and follow the veins at their ends. They contain tan spores. [2]

Among its congeners in Mexico, M. allosuroides is similar to M. cucullans and M. notholaenoides in its largely undifferentiated false indusia and elongate sori along veins, but those species have more indument on their leaf tissue and lack the groove on the stipe and rachis. [2] M. mickelii also has the grooved stipe and rachis, but is hairy above and below. [1] M. wrightii is also similar in having a grooved stipe and rachis and nearly glabrous fronds, but its false indusia are broken into interrupted lobes rather than being continuous. [2]

Taxonomy

Myriopteris allosuroides was first described by Georg Heinrich Mettenius in 1859, as Cheilanthes allosuroides. He based it on material collected in Mexico by Eugénio Schmitz. [4] The epithet allosuroides, a compound meaning "resembling Allosorus ", [5] presumably reflects the similarity of the species to those which Mettenius placed in Allosorus, particularly in bearing long sori along the veins. [6] In 1877, the difference in sori and false indusia led Conde Vittore Trevisan to create a new genus, Cheilosoria , for C. allosuroides and a few other species of Cheilanthes . [7] In 1920, Georg Hieronymus transferred the species to Pellaea . [8]

The development of molecular phylogenetic methods showed that the traditional circumscription of Cheilanthes is polyphyletic. Convergent evolution in arid environments is thought to be responsible for widespread homoplasy in the morphological characters traditionally used to classify it and the segregate genera that have sometimes been recognized. On the basis of molecular evidence, Amanda Grusz and Michael D. Windham revived the genus Myriopteris in 2013 for a group of species formerly placed in Cheilanthes. One of these was C. allosuroides, which thus became Myriopteris allosuroides. [9] In 2018, Maarten J. M. Christenhusz transferred the species to Hemionitis as H. allosuroides, as part of a program to consolidate the cheilanthoid ferns into that genus. [10]

Further molecular studies in Myriopteris demonstrated the existence of three well-supported clades within the genus. M. allosuroides belongs to what Grusz et al. informally named the alabamensis clade, and is sister to a group consisting of M. mickelii , M. pringlei , and M. peninsularis . [11]

In the second edition of their Synopsis Filicum of 1874, William Jackson Hooker and John Gilbert Baker recognized Cheilanthes allosuroides, [12] and Baker also described a new species, Pellaea pallida, based on material collected by Glennie in Mexico. The epithet pallida, meaning "pale", [13] presumably reflects the leaf color, described as "pale grey-green". [14] They placed this species in Pellaea because of fairly continuous margins around the leaf edges. [15] As part of his wide-ranging program of taxonomic revision, Otto Kuntze argued that the principle of priority precluded the use of the generic name Pellaea, and transferred the species to the older genus Allosorus as Allosorus pallidus in 1891. [16] This combination was rendered unnecessary when Pellaea and Cheilanthes were conserved over Allosorus in the Paris Code published in 1956. After examination of the type material at Kew, John T. Mickel and Alan R. Smith placed this species in synonymy with C. allosuroides in 2004, [2] although Christenhusz recognized it as distinct and transferred it separately to Hemionitis as H. pallida in 2018. [10]

Konrad H. Christ, in 1910, described Pellaea arsenei (as "arsenii") from material collected by G. Arsène in Michoacán in 1909, naming it for the collector. He considered it very similar to Pellaea seemannii (now Cheilanthes lozanoi var. seemannii ), but distinguished by its lack of indument on stipe and rachis. [17] Hieronymus considered this material identical with Cheilanthes allosuroides in 1920, but agreed with Christ that the species has close affinities to P. seemannii and hence transferred the senior name to that genus; he also noted a close resemblance to P. scabra, now Myriopteris scabra . [8] Oliver Atkins Farwell, following, like Kuntze, a program of reviving what he considered to be senior synonyms, gave Cassebeera priority over Pellaea and transferred P. arsenei to that genus as Cassebeera arsenei. [18]

Distribution and habitat

Myriopteris allosuroides grows throughout most of Mexico, but is absent from the Baja Peninsula and the northeastern and extreme southeastern provinces, the southward range ending in Veracruz and Oaxaca. [2]

The species grows on dry, rocky slopes over acidic bedrock, particularly basaltic rocks. It is found at altitudes from 1,000 to 2,400 meters (3,300 to 7,900 ft). [2]

Notes and references

Related Research Articles

<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>Myriopteris cooperae</i> Species of fern

Myriopteris cooperae, formerly Cheilanthes cooperae, is a species of lip fern known by the common name Mrs. Cooper's lip fern, or simply Cooper's lip fern.

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

Myriopteris gracillima, formerly known as Cheilanthes gracillima, is a species of lip fern known by the common name lace lip fern. It is native to western North America, where it grows in rocky habitat from British Columbia to California to Montana.

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

Myriopteris tomentosa, formerly known as Cheilanthes tomentosa, is a perennial fern known as woolly lipfern. Woolly lipfern is native to the southern United States, from Virginia to Arizona and Georgia, and Mexico.

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

Myriopteris lanosa, the hairy lip fern, is a moderately-sized fern of the eastern United States, a member of the family Pteridaceae. Its leaves and stem are sparsely covered in hairs, but lack scales, hence its common name. One of the cheilanthoid ferns, it was usually classified in the genus Cheilanthes until 2013, when the genus Myriopteris was again recognized as separate from Cheilanthes. It typically grows in shallow, dry, soil, often in rocky habitats.

<i>Myriopteris</i> Genus of ferns

Myriopteris, commonly known as the lip ferns, is a genus of cheilanthoid ferns. Like other cheilanthoids, they are ferns of dry habitats, reproducing both sexually and apogamously. Many species have leaves divided into a large number of small, bead-like segments, the probable inspiration for the generic name. Hairs and/or scales are often present on both the upper and lower surfaces of the leaf, and their presence and appearance are useful in distinguishing between species. The genus is most diverse in Mexico, but species are found from southwestern Canada south to southern Chile, and one species is endemic to southern Africa.

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

Myriopteris alabamensis, the Alabama lip fern, is a moderately-sized fern of the United States 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 alabamensis until 2013, when the genus Myriopteris was again recognized as separate from Cheilanthes. It typically grows in shade on limestone outcrops.

Myriopteris maxoniana is a species of cheilanthoid fern known only from one collection in Tamaulipas, Mexico. It closely resembles Myriopteris longipila and was not described as a distinct taxon until 2004.

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.

Myriopteris yatskievychiana is a small fern native to Mexico, a member of the family Pteridaceae. It is known only from a single collection in the Mexican state of Sonora. While superficially similar to golden lip fern, a widespread species in Mexico, differences in its coating of hairs and its small size make it distinctive. One of the cheilanthoid ferns, it was usually classified in the genus Cheilanthes until 2013, when the genus Myriopteris was again recognized as separate from Cheilanthes.

<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".

<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.

<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".

<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 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".

<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.

Myriopteris longipila, formerly known as Cheilanthes longipila, is a species of fern native to Mexico. It is characterized by a dense covering of long whitish hairs.

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

Myriopteris rawsonii, formerly known as Cheilanthes rawsonii, is a perennial fern native to Namaqualand in Southern Africa. Like many other cheilanthoid ferns, it is adapted to dry conditions, bearing a thick layer of pale hairs on the underside of its pinnate-pinnatifid leaves. It is the only African representative of its clade of cheilanthoids, the otherwise American genus Myriopteris. It spends much of the year in a dried-out, dormant state, rehydrating and putting out new growth during winter rains. Its name honors the botanist and civil servant Sir Rawson W. Rawson.

Myriopteris chipinquensis is a fern endemic to Mexico, a member of the family Pteridaceae. One of the cheilanthoid ferns, it was classified in the genus Cheilanthes until 2013, when the genus Myriopteris was again recognized as separate from Cheilanthes. It grows in oak-pine forests of the Sierra Madre Oriental, often with the very similar and closely related Myriopteris tomentosa.

References

  1. 1 2 3 Mickel & Smith 2004, p. 178.
  2. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 Mickel & Smith 2004, p. 181.
  3. ↑ Grusz et al. 2014, p. 705.
  4. ↑ Mettenius 1859, p. 76.
  5. ↑ Short & George 2013, p. 219.
  6. ↑ Mettenius 1859, p. 49.
  7. ↑ Trevisan 1877, p. 579.
  8. 1 2 Hieronymus 1920, p. 18.
  9. ↑ Grusz & Windham 2013.
  10. 1 2 Christenhusz, Fay & Byng 2018, p. 9.
  11. ↑ Grusz et al. 2014, p. 704.
  12. ↑ Hooker & Baker 1874, p. 137.
  13. ↑ Short & George 2013, p. 223.
  14. ↑ Hooker & Baker 1874, p. 478.
  15. ↑ Hooker & Baker 1874, p. 144.
  16. ↑ Kuntze 1891, pp. 804–806.
  17. ↑ Christ 1910, p. 233.
  18. ↑ Farwell 1931, p. 281.

Works cited

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