Fissidens taxifolius, the common pocket moss,[1] is a species of moss in the family Fissidentaceae. First described by Johann Hedwig in 1801, it is a small to medium-sized moss that typically grows in dense, yellowish-green to dark green tufts. The species is characterised by its distinctive flattened appearance, with leaves arranged in two opposite rows resembling tiny fern fronds, and by its pointed leaf tips with projecting central nerves. It can grow in artificial light and is known to form extensive turfs in suitable conditions.
The species has a nearly cosmopolitan distribution, being particularly common in the Northern Hemisphere across Europe, North America, Asia, and Africa, with populations in the Pacific region. While primarily growing on soil and soil-covered rocks in wet, shaded areas, it also occurs in modified environments such as urban parks and gardens. The species shows significant regional variation in both morphology and reproduction. In Europe and North America, populations are typically autoicous, with both male and female organs on the same plant, and readily produce spores, whereas Pacific populations are often dioicous and reproduce primarily through vegetative means. Fissidens taxifolius is assessed as a least-concern species on the IUCN Red List due to its large, stable populations across its range and the lack of major threats to its survival.
Taxonomy
Johann Hedwig formally describedFissidens taxifolius in his 1801 work Species Muscorum Frondosorum. In this protologue, Hedwig provided a simple morphological description of the species, characterising it as having a simple, erect stem that is pinnate-leaved, originating from a basal point that produces both new shoots and fertile structures. He also noted that the peduncles are curved at their tips. The leaves are arranged in two rows, ovate-lanceolate in shape, and the capsule is somewhat nodding and oblong, with a beaked operculum. Hedwig referenced previous descriptions by other bryologists, including Johann Christian Daniel von Schreber (citing Hedwig’s earlier works), Carl Linnaeus, Johann Jacob Dillenius, and Sébastien Vaillant, connecting Fissidens taxifolius to several names used previously, such as Hypnum taxifolium and Hypnum laxiforme minus. He stated that the species was widespread across Europe, typically found in moist, shady depressions.[3]
The species nametaxifolius refers to the resemblance of its leaves to those of yew trees (genus Taxus). The lectotype specimen, which serves as the definitive reference for the species, is housed in the Hedwig-Schwaegrichen collection at the herbarium in Geneva. The specimen bears Hedwig's handwritten label referencing Linnaeus's Species Plantarum and Dillenius's Historia Muscorum, and forms the basis for its current classification.[4][5]
Fissidens taxifolius shows notable variation in certain characteristics across its global range. For instance, some morphological features, such as the degree of roughness of the leaf cells and the extent to which the central nerve projects beyond the leaf tip, can vary significantly between populations. In Europe and North America, it is "autoicous" (having both male and female reproductive organs on the same plant). However, in areas such as New Zealand, Hawaii, and Papua New Guinea, it appears to be "dioicous" (having male and female reproductive organs on separate plants).[4]
The species is well-established in taxonomic literature, with over 400 years of documented history. It is considered one of the more distinctive members of the genus Fissidens, though it can be confused with similar species in regions where their ranges overlap. The taxonomic placement of Fissidens taxifolius has remained stable, without major revisions or name changes, making it one of the most stable bryophyte species.[4]
Description
Fissidens taxifolius is a small to medium-sized moss. It typically grows in dense, yellowish-green to dark green tufts. The plant's upright stems grow 5–22mm tall and up to 4 mm wide, often branching from the base. Like other members of the genus Fissidens, it has a distinctive flattened appearance, with leaves arranged in two opposite rows that resemble a tiny fern frond.[4]
The individual leaves are oblong- lanceolate (spear-shaped) and measure 1.4–2.4mm in length. A notable characteristic is the leaf tip, which comes to a sharp point (acute) and usually extends into a small projection ( mucro or cusp ). The leaves have a unique folded structure typical of Fissidens species, with the lower portion forming a sheath that wraps around the stem for half to two-thirds of the leaf length.[4] The species produces smooth rhizoids, unlike some related species like F.osmundoides which has papillose rhizoids (covered with small bumps).[6]
Each leaf has a strong central nerve (costa) that typically extends beyond the leaf tip. The leaf margins are finely toothed ( serrulate ). The cells making up the leaf surface are small, square to hexagonal in shape, and slightly bulging, giving the leaves a cloudy or opaque appearance. These cells measure about 8–10micrometres (μm) in length, with some variation.[4]
The species can reproduce both sexually and asexually. For asexual reproduction, it sometimes produces small structures called rhizoidal tubers, which measure 150–380μm in diameter. Old shoots often show evidence of animal grazing, with eroded leaf surfaces. In its New Zealand populations, only female plants have been found. No male organs or spore capsules have been observed, suggesting the vegetative reproduction.[4] Archegonia are about 300μm long, and the antheridia 120μm long.[7]
When dry, the leaves remain relatively straight or become slightly twisted in their upper portions, rather than curling dramatically as some mosses do. The species can be distinguished from similar Fissidens species by its tufted growth habit and the distinctive pointed leaf tips with their projecting central nerve.[4]
There is distinct variation in morphological features across the species' global range. For example, the roughness of leaf cells and the extent to which the central nerve projects beyond the leaf tip can vary significantly between populations. European and North American specimens typically have bumpy ( mammillose ) leaf cells, while some Pacific populations show less pronounced cell surface features.[8]
Microscopic features
Typical frond-like appearance showing the characteristic two-ranked leaf arrangement and pointed leaf tips. Scale bar: 1 mm
Spore capsule (sporangium) showing the reddish-brown colouration and characteristic opening. Scale bar: 0.5 mm
Microscopic view of a single leaf showing the characteristic central nerve ( costa ) and small, hexagonal cells of the leaf surface. Scale bar: 200 μm.
Variability
Fissidens taxifolius var. pallidicaulis is a type found in the Southern-Temperate Oceanic region. It differs from the typical form primarily by its taller shoots, reaching up to 3cm in height (and even up to 6cm in Madeira). The leaves are usually lance-shaped to narrow lance-shaped, tapering to a pointed tip from the end of the sheathing base. Additionally, the leaf cells are 7–9μm wide in the central part of the upper leaf. However, this variety is considered of doubtful taxonomic value.[7]
Reproduction
The species exhibits different reproductive patterns across its range. In Europe and North America, it is autoicous, meaning both male and female reproductive organs are found on the same plant. However, in other regions including New Zealand, Hawaii, and Papua New Guinea, populations appear to be dioicous, with male and female reproductive organs on separate plants. In some Pacific regions, only female plants have been found, and the species appears to reproduce primarily through vegetative means rather than spore production.[8]
Similar species
Fissidens taxifolius can be confused with several similar species where their ranges overlap. An example is Fissidens nothotaxifolius, which closely resembles F.taxifolius but can be distinguished by its pluripapillose cells (cells with multiple small protrusions), particularly prominent on the vaginant laminae (the sheathing portion of the leaf). These papillae require careful microscopic examination to observe and are best seen in cross-section. Another distinguishing feature of F.nothotaxifolius is its conspicuously whitened costae (central nerves) contrasting with very dark green leaves, and its leaves tend to be more undulate (wavy) than those of F.taxifolius.[8]
Two other species that may be confused with F.taxifolius due to their similar size and unbordered leaves are Fissidens asplenioides and F.oblongifolius. However, F.taxifolius is readily distinguished from both by its characteristic tufted growth habit and its mucronate to cuspidate leaf apices (tips that end in a sharp point) containing a percurrent or excurrent nerve (a central nerve that reaches or extends beyond the leaf tip).[4]
Some forms of Fissidens pacificus can also resemble F.taxifolius, particularly when certain diagnostic features are poorly expressed. The key difference lies in the cell size, with F.pacificus having larger laminal cells (9–13μm) compared to those of F.taxifolius (7–9μm). F.pacificus can also be identified by the presence of a paler marginal band of cells.[8]
Another lookalike, F. bushii can be distinguished by its dark-green colour, irregularly bistratose leaf laminae (having two cell layers), broadly acute to rounded obtuse leaf apices, and slender costae that usually end in the apiculi. The most reliable way to separate the two species is by examining the vaginant lamina cells in cross-section: in F.bushii the cells are pluripapillose (having multiple small protrusions), while in F.taxifolius they are mammillose (having larger, rounded protrusions).[6]
Habitat, distribution, and ecology
Dense turf of F. taxifolius showing its typical growth habit in a shaded, moist habitat. The fern-like arrangement of leaves is clearly visible.
Fissidens taxifolius has an incompletely cosmopolitan distribution, being particularly common in the Northern Hemisphere. The species has been documented across Europe, North and South America, Asia, Africa, and the Pacific region. It is absent from Antarctica, very rare in sub-Saharan Africa, and not known from Australia. The species is rare or absent in boreal and arctic regions. It has an exceptionally wide presence, occurring in Algeria, Armenia, Austria, Bermuda, Brazil, Burma, Canada, Chad, Cuba, Denmark, Dominican Republic, Egypt, France, Germany, Guatemala, Haiti Islands, Honduras, Ireland, Japan, Mexico, Netherlands, New Zealand, Norway, Papua New Guinea, Poland, Portugal, Russia, Spain, Sweden, Switzerland, Taiwan, Thailand, Turkey, United Kingdom, and United States of America.[9][1]
Fissidens taxifolius is known to be able to use artificial light to grow in places which are otherwise devoid of natural light, such as Crystal Cave in Wisconsin.[10]
Habitat and ecology
The species typically grows on bare earth in lightly shaded conditions, forming extensive turfs that can cover several square metres when conditions are favourable. It is particularly characteristic of woodland and forest on base-rich and neutral soils, and commonly occurs in stream valleys and rocky slopes. It occurs in both modified and natural environments, including urban parks, gardens, suburban lawns, roadside areas, forest tracks, and shaded banks. While primarily growing on soil and soil-covered rocks in wet, shaded areas, it occasionally grows epiphytically on tree bark.[4][9][1]
Fissidens taxifolius commonly grows alongside other moss species, particularly Fissidens pungens, Fissidens leptocladus, and Stokesiella praelonga. The species shows adaptations for survival and spread, including vegetative reproduction through plant fragments and specialised underground rhizoidal tubers. Evidence of animal grazing on the leaves suggests it forms part of the diet of small invertebrates.[4]
In the Pacific region, elevation ranges vary significantly. Hawaiian populations occur primarily at high elevations within 300 metres of the timber line, growing on loose, protected soil banks. In Papua New Guinea, it has been found in 28 localities between 1,400 and 2,900 metres elevation, primarily in forests.[8]
In New Zealand, F.taxifolius exists as an introduced species, occurring from sea level to 325 metres elevation. The species shows a clear preference for warmer regions, predominantly appearing in areas with mean annual temperatures above 12.5°C, particularly in the northern regions of the North Island, with scattered populations extending south to Nelson. Several factors support its classification as an introduced species: the moss is found almost exclusively in disturbed habitats and modified environments, only female plants have been documented (with reproduction occurring solely through vegetative means), and despite extensive botanical surveys, no specimens were collected prior to 1966. Additionally, its distribution appears to be constrained by temperature requirements, further suggesting its non-native status.[4]
Regional populations show distinct reproductive patterns: while the species produces spore capsules readily in Europe and North America, Pacific populations (including New Zealand, Hawaii, and Papua New Guinea) reproduce primarily through vegetative means, suggesting either environmental limitations or single-gender populations.[8][4]
Conservation
Fissidens taxifolius is assessed as a least-concern species (LC) on the IUCN Red List. The species maintains large, stable populations across its range and faces no major threats to its survival. While it occurs naturally in various woodland and forest habitats, it has also successfully adapted to human-modified environments including urban parks and cultivated land. The species is present in multiple protected areas and requires no specific conservation measures. Its absence from Australia and rarity in sub-Saharan Africa appear to reflect natural distribution patterns rather than conservation concerns.[1]
Related Research Articles
Fissidens adianthoides, the maidenhair pocketmoss, is a moss in the family Fissidentaceae. It was first collected by Hedwig in 1801.
Monoicy is a sexual system in haploid plants where both sperm and eggs are produced on the same gametophyte, in contrast with dioicy, where each gametophyte produces only sperm or eggs but never both. Both monoicous and dioicous gametophytes produce gametes in gametangia by mitosis rather than meiosis, so that sperm and eggs are genetically identical with their parent gametophyte.
Polytrichum commune is a species of moss found in many regions with high humidity and rainfall. The species can be exceptionally tall for a moss with stems often exceeding 30 cm (12 in) and rarely reaching 70 cm (27.5 in), but it is most commonly found at shorter lengths of 5 to 10 cm. It is widely distributed throughout temperate and boreal latitudes in the Northern Hemisphere and also found in Mexico, several Pacific Islands including New Zealand, and also in Australia. It typically grows in bogs, wet heathland and along forest streams. Additionally, class Polytrichopsida has been shown to thrive in partially open habitats that have been recently disturbed by human activities or even livestock.
Meesia uliginosa, the broad-nerved hump-moss, is a rare moss of the Western U.S. It occurs all around the northern hemisphere in higher latitudes, and in some places is not as rare as in the Western U.S.
Fissidens hydropogon is a species of moss in the family Fissidentaceae. It is a critically endangered species endemic to Ecuador.
Spruceanthus theobromae is a species of liverwort in the family Lejeuneaceae. It is endemic to Ecuador, where it is the only liverwort species known to be endemic to the western foothills of the Ecuadorian Andes.
Rhytidiadelphus squarrosus is a species of moss known as springy turf-moss in the United Kingdom, and square goose neck moss in the United States. It is widespread in Eurasia and North America, and has been introduced to the Southern Hemisphere. It has broad ecological tolerances, and is usually found in man-made habitats such as lawns and golf courses. It is most closely related to R. subpinnatus, with which it is often confused.
Splachnaceae is a family of mosses, containing around 70 species in 6 genera. Around half of those species are entomophilous, using insects to disperse their spores, a characteristic found in no other seedless land plants.
Sphagnum fimbriatum, the fringed bogmoss, is a peat moss found in temperate regions worldwide, from the Arctic to New Zealand and along the Andes. William Wilson formally described the species in 1846. Plants measure up to 10 cm (4 in) tall, varying from slender to moderately robust forms. It forms loose carpets or soft mounds in wetlands and is identified by its stem leaves with fringed upper margins. The stem leaves distinguish it from other Sphagnum species, including its close relative S. girgensohnii which has rectangular stem leaves fringed only at the tip.
Cyathophorum bulbosum, commonly known as quill moss or the false fern moss, is found in the eastern states of Australia as well as Papua New Guinea, New Zealand, Auckland Islands, Chatham Island, Lord Howe Island and possibly Norfolk Island and New Ireland.
Bartramia is a genus of mosses in the family Bartramiaceae. The genus was first formally described by Johann Hedwig in 1801. There are about 72 species, usually growing on soil, sometimes on rocks, in many habitats in many parts of the world, although tropical species are only found at high altitudes. Nine species occur in Australia but only three of these are endemic to that continent.
Fissidens limbatus commonly known as Herzog's pocket-moss, is a moss in the family Fissidentaceae. This species is found growing in high elevations in tropical America in addition to the US, Mexico and Canada. Montagne first collected F. crispus in 1838.
Ulota is a genus of mosses comprising 69 species with a worldwide distribution, though most species are found in the southern hemisphere.
Tortula muralis, commonly known as wall-screw moss, is a species of moss in the family Pottiaceae. T. muralis is found throughout the world.
Ptychostomum pseudotriquetrum, commonly known as marsh bryum, is a species of moss belonging to the family Bryaceae. It is distinguished by its strongly decurrent leaves that extend down the stem, central leaf stalks which may extend slightly beyond the tip of the leaf, dioicy, and long stems densely matted with rhizoids. It is found worldwide, excluding the tropics.
Fissidens dubius, commonly known as the rock-pocket moss, is a species of moss belonging to the family Fissidentaceae. First described by Palisot de Beauvois in 1805 from material collected in Philadelphia, it is a relatively large moss growing up to 5 cm (2 in) tall that forms loose to dense mats on calcareous substrates. The species is characterised by its serrated leaf margins, pale border of thick-walled cells, and typically dioicous reproduction. It has a broad global distribution across Europe, North and South America, Asia, North Africa, and New Zealand, occurring in various habitats from lowlands to alpine zones, particularly in shaded locations on basic soils and rocks. While morphologically similar to F. adianthoides, F. dubius is distinguished by its smaller leaf cells and irregularly thickened leaf tips. The species is classified as Least Concern due to its stable populations and absence of major threats.
Polytrichastrum formosum, commonly known as the bank haircap moss, is a species of moss belonging to the family Polytrichaceae.
Andreaea blyttii, also commonly known as Blytt's rock moss, is a moss belonging to the family Andreaeaceae, commonly known as rock moss, granite moss, or lantern moss because of this family's unique sporangium. It is part of the genus Andreaea which is known for forming dark brownish or reddish-black carpets in high elevations. This species was first described by Schimper in 1855.
Fissidens usambaricus is a species of moss belonging to the family Fissidentaceae. It is known from Sub-Saharan Africa, where it is found in a variety of forest types. In Angola, it has been reported to grow in lowland rainforests.
Fissidens celticus, also known by its common name Welsh pocket-moss, is a species of moss in the family Fissidentaceae. It was discovered in 1958 in Pembrokeshire by A.H. Norkett and was first described as a new species by Jean Paton in 1965.
↑ Pursell, Ronald A. (1986). "Typification of Hedwig's species of Fissidens". The Bryologist. 89 (1): 35–41. doi:10.2307/3243075. JSTOR3243075.
1 2 3 Pursell, Ronald A.; Allen, Bruce (2017). "Fissidens of Delaware and adjacent areas". Evansia. 34 (4): 134–151. doi:10.1639/0747-9859-34.4.134.
1 2 Erzberger, Peter (2016). "The genus Fissidens (Fissidentaceae, Bryophyta) in Hungary". Studia Botanica Hungarica. 47 (1): 41–139. doi:10.17110/StudBot.2016.47.1.41.
1 2 3 4 5 6 Pursell, Ronald A.; Hoe, William J. (1977). "Fissidens in Hawaii". Journal of the Hattori Botanical Laboratory. 43: 81–106.
This page is based on this Wikipedia article Text is available under the CC BY-SA 4.0 license; additional terms may apply. Images, videos and audio are available under their respective licenses.
