Dryopteris intermedia | |
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Scientific classification | |
Kingdom: | Plantae |
Clade: | Tracheophytes |
Division: | Polypodiophyta |
Class: | Polypodiopsida |
Order: | Polypodiales |
Suborder: | Polypodiineae |
Family: | Dryopteridaceae |
Genus: | Dryopteris |
Species: | D. intermedia |
Binomial name | |
Dryopteris intermedia (Muhl. ex Willd.) A.Gray | |
Synonyms [2] [3] [4] | |
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Dryopteris intermedia, the intermediate wood fern or evergreen wood fern, [4] [3] is a perennial, evergreen wood fern native to eastern North America. It is a diploid species, and is the parent of several species of hybrid origin, including Dryopteris carthusiana . Other common names for this species include intermediate shield fern, fancy wood fern, fancy fern, glandular wood fern, American shield fern and common wood fern. [2] [3] [5] [6]
This fern is often confused with several other wood fern species, including D. carthusiana, D. campyloptera , and D. expansa . It especially extensively shares the range of D. carthusiana, but the two may be distinguished by the innermost pinnule on the bottom side of the bottom pinna: this pinnule is longer than the adjacent pinnules in D. carthusiana, but shorter or even in D. intermedia.
Dryopteris intermedia is a perennial fern that grows to a size of about 40–90 cm (16–35 in) tall and 60–90 cm (24–35 in) wide. [6] At its base, it consists of an underground rhizome from which grow the fronds of the plant in a spiral-like arrangement. Each frond consists of a stipe (stalk) that is covered in light-brown scales towards the base and short glandular hairs further up. [5] [6] The stipes generally measure between 1/4 to 1/3 the length of the frond [6] and support a leaf blade that is lance-oblong [5] in shape. The leaves themselves are bipinnately compound, [6] meaning that they divide into leaflets called pinnae and sub-leaflets called pinnules. The pinnules of this species are lobed and toothed. [5] Uniquely, the first pinnule closest to the stem on the lowest pinna is shorter than the second. [5]
Dryopteris intermedia is native to most of eastern North America, ranging from Minnesota in the north-west and Newfoundland and Labrador in the north-east, down to Alabama in the south-west and South Carolina in the south-east. [3] [4] While globally secure, it is considered by NatureServe to be "critically imperiled" in the states of Iowa and Missouri which represent the western limit of its range, and "imperiled" in the states of Illinois and South Carolina as well as the region of Labrador. [1] Similar ferns found in the Azores are often regarded as a subspecies (subsp. azorica) or as a different species (Dryopteris azorica). [7]
Dryopteris intermedia grows in a variety of mesic habitats including forests, woodlands, ravines, swamp edges and rocky slopes. [5] [6]
Dryopteris intermedia is cultivated as an ornamental plant in North America for gardens, especially natural gardens and shade gardens, as it is easy to grow in a range of environments and soils and does not spread much. [6] Care needs to be taken when planting to ensure that the fern is placed in an area of part-shade or full-shade and that the soil remains moist, as it does not tolerate a lot of sun or dry soil. [6]
Several naturally occurring hybrids involving Dryopteris intermedia exist. These include: [3]
All of the hybrids listed above are sterile. One exception is the allotetraploid Dryopteris carthusiana (spinulose wood fern), which is said to originate from a hybridization of Dryopteris intermedia and an extinct fern dubbed Dryopteris "semicristata". [8]
Dryopteris, commonly called the wood ferns, male ferns, or buckler ferns, is a fern genus in the family Dryopteridaceae, subfamily Dryopteridoideae, according to the Pteridophyte Phylogeny Group classification of 2016 (PPG I). There are about 300-400 species in the genus. The species are distributed in Asia, the Americas, Europe, Africa, and the Pacific islands, with the highest diversity in eastern Asia. It is placed in the family Dryopteridaceae, subfamily Dryopteridoideae, according to the Pteridophyte Phylogeny Group classification of 2016 (PPG I). Many of the species have stout, slowly creeping rootstocks that form a crown, with a vase-like ring of fronds. The sori are round, with a peltate indusium. The stipes have prominent scales.
Dryopteris expansa, the alpine buckler fern, northern buckler-fern or spreading wood fern, is a species of fern native to cool temperate and subarctic regions of the Northern Hemisphere, south at high altitudes in mountains to Spain and Greece in southern Europe, to Japan in eastern Asia, and to central California in North America. The species was first described from Germany. It prefers cool, moist mixed or evergreen forests and rock crevices on alpine slopes, often growing on rotting logs and tree stumps and rocky slopes. It is characteristically riparian in nature, and is especially associated with stream banks.
Polystichum aculeatum, the hard shield-fern, is an evergreen fern native to Europe. It is most abundant in upland regions of the Atlantic Archipelago and western France, where it benefits from the combination of mild winters and moist summers, but also occurs more locally across most of Europe except northern Scandinavia, northern Russia; in the Mediterranean region it is confined to high altitudes. It grows on steep slopes in woodlands. it is sometimes considered an indicator of the presence of ancient woodlands.
Dryopteris affinis, the scaly male fern or golden-scaled male fern, is a fern native to western and southern Europe and southwestern Asia. It is most abundant on moist soils in woodlands in areas with high humidity, such as the British Isles and western France. In the Mediterranean region and the Caucasus it is confined to high altitudes.
Dryopteris marginalis, vernacularly known as the marginal shield fern or marginal wood fern, is a perennial species of fern found in damp shady areas throughout eastern North America, from Texas to Minnesota and Newfoundland. It favors moderately acid to circumneutral soils in cooler areas but is fairly drought-resistant once established. In the warmer parts of its range, it is most likely to be found on north-facing non-calcareous rock faces. It is common in many altitudes throughout its range, from high ledges to rocky slopes and stream banks. Marginal wood fern's name derives from the fact that the sori are located on the margins, or edges of the leaflets.
Polystichum acrostichoides, commonly denominated Christmas fern, is a perennial, evergreen fern native to eastern North America, from Nova Scotia west to Minnesota and south to Florida and eastern Texas. It is one of the most common ferns in eastern North America, being found in moist and shady habitats in woodlands, stream banks and rocky slopes. The common name derives from the evergreen fronds, which are often still green at Christmas.
Dryopteris ludoviciana, the southern woodfern, is fern native to southern United States from Florida west to Texas and as far north as Kentucky and North Carolina.
Dryopteris carthusiana is a species of fern native to damp forests throughout the Holarctic Kingdom. It is known as the narrow buckler-fern in the United Kingdom, and as the spinulose woodfern in North America.
Dryopteris cristata is a species of fern native to wetlands throughout the Northern Hemisphere. It is known as crested wood fern or crested buckler-fern. This plant is a tetraploid species of hybrid origin, one parent being Dryopteris ludoviciana and the other being the unknown, apparently extinct species, dubbed Dryopteris semicristata, which is also one of the presumed parents of Dryopteris carthusiana. D. cristata in turn is one of the parents of Dryopteris clintoniana, another fern of hybrid origin.
Dryopteris goldieana, commonly called Goldie's wood fern, or giant wood fern is a fern native to the eastern United States and adjacent areas of Canada, from New Brunswick to Ontario and Georgia. It is the largest native North American species of Dryopteris and along with ostrich fern it is one of the largest ferns in eastern North America. Specimens are known with fronds six feet tall. D. goldieana hybridizes with many other species of Dryopteris and the hybrids tend to be larger than the pure species. It was named by William Hooker in honor of its discoverer, John Goldie. The epithet was originally published as goldiana, but this is regarded as a misspelling to be corrected.
Dryopteris campyloptera, also known as the mountain wood fern, is a large American fern of higher elevations and latitudes. It was formerly known as Dryopteris spinulosa var. americana. This species also has been mistakenly referred to D. austriaca and D. dilatata.
Hybridization and polyploidy are common phenomena in ferns, and the genus Dryopteris is known to be one of the most freely-hybridizing fern genera. North American botanists recognized early that there were close relationships between many of the species of Dryopteris on the continent, and that these relationships reflected hybrid ancestry. The complex includes six sexual diploid parents, six sexual allopolyploids, and numerous sterile hybrids at various ploidal levels.
Asplenium montanum, commonly known as the mountain spleenwort, is a small fern endemic to the eastern United States. It is found primarily in the Appalachian Mountains from Vermont to Alabama, with a few isolated populations in the Ozarks and in the Ohio Valley. It grows in small crevices in sandstone cliffs with highly acid soil, where it is usually the only vascular plant occupying that ecological niche. It can be recognized by its tufts of dark blue-green, highly divided leaves. The species was first described in 1810 by the botanist Carl Ludwig Willdenow. No subspecies have been described, although a discolored and highly dissected form was reported from the Shawangunk Mountains in 1974. Asplenium montanum is a diploid member of the "Appalachian Asplenium complex," a group of spleenwort species and hybrids which have formed by reticulate evolution. Members of the complex descended from A. montanum are among the few other vascular plants that can tolerate its typical habitat.
Asplenium pinnatifidum, commonly known as the lobed spleenwort or pinnatifid spleenwort, is a small fern found principally in the Appalachian Mountains and the Shawnee Hills, growing in rock crevices in moderately acid to subacid strata. Originally identified as a variety of walking fern, it was classified as a separate species by Thomas Nuttall in 1818. It is believed to have originated by chromosome doubling in a hybrid between walking fern and mountain spleenwort, producing a fertile tetraploid, a phenomenon known as alloploidy; however, the hypothesized parental hybrid has never been located. It is intermediate in morphology between the parent species: while its leaf blades are long and tapering like that of walking fern, the influence of mountain spleenwort means that the blades are lobed, rather than whole. A. pinnatifidum can itself form sterile hybrids with several other spleenworts.
Asplenium bradleyi, commonly known as Bradley's spleenwort or cliff spleenwort, is a rare epipetric fern of east-central North America. Named after Professor Frank Howe Bradley, who first collected it in Tennessee, it may be found infrequently throughout much of the Appalachian Mountains, the Ozarks, and the Ouachita Mountains, growing in small crevices on exposed sandstone cliffs. The species originated as a hybrid between mountain spleenwort and ebony spleenwort ; A. bradleyi originated when that sterile diploid hybrid underwent chromosome doubling to become a fertile tetraploid, a phenomenon known as allopolyploidy. Studies indicate that the present population of Bradley's spleenwort arose from several independent doublings of sterile diploid hybrids. A. bradleyi can also form sterile hybrids with several other spleenworts.
Gymnocarpium robertianum, the limestone fern or scented oakfern, is a fern of the family Cystopteridaceae.
Adiantum viridimontanum, commonly known as Green Mountain maidenhair fern, is a rare fern found only in outcrops of serpentine rock in New England and Eastern Canada. The leaf blade is cut into finger-like segments, themselves once-divided, which are borne on the outer side of a curved, dark, glossy rachis. These finger-like segments are not individual leaves, but parts of a single compound leaf. The "fingers" may be drooping or erect, depending on whether the individual fern grows in shade or sunlight. Spores are borne under false indusia at the edge of the subdivisions of the leaf, a characteristic unique to the genus Adiantum.
Dryopteris macropholis is a species of fern. It is distributed on the Marquesas Islands.
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.
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