''Selaginella'' is the sole genus of

vascular plant Vascular plants (), also called tracheophytes () or collectively Tracheophyta (), form a large group of land plants ( accepted known species) that have lignified tissues (the xylem) for conducting water and minerals throughout the plant. They ...

s in the family Selaginellaceae, the spikemosses or lesser clubmosses. This family is distinguished from

Lycopodiaceae The Lycopodiaceae (class Lycopodiopsida, order Lycopodiales) are an old family of vascular plants, including all of the core clubmosses and firmosses, comprising 16 accepted genera and about 400 known species. This family originated about 380 mil ...

(the clubmosses) by having scale-leaves bearing a ligule and by having spores of two types. They are sometimes included in an informal paraphyletic group called the "

fern allies Fern allies are a diverse group of seedless vascular plants that are not true ferns. Like ferns, a fern ally disperses by shedding spores to initiate an alternation of generations. Classification Originally, three or four groups of plants were ...

". '' S. moellendorffii'' is an important

model organism A model organism (often shortened to model) is a non-human species that is extensively studied to understand particular biological phenomena, with the expectation that discoveries made in the model organism will provide insight into the working ...

. Its genome has been sequenced by the

United States Department of Energy The United States Department of Energy (DOE) is an executive department of the U.S. federal government that oversees U.S. national energy policy and manages the research and development of nuclear power and nuclear weapons in the United State ...

Joint Genome Institute The U.S. Department of Energy (DOE) Joint Genome Institute (JGI), first located in Walnut Creek then Berkeley, California, was created in 1997 to unite the expertise and resources in genome mapping, DNA sequencing, technology development, and ...

. The name ''Selaginella'' was erected by Palisot de Beauvois solely for the species '' Selaginella selaginoides'', which turns out (with the closely related ''

Selaginella deflexa ''Selaginella'' is the sole genus of vascular plants in the family Selaginellaceae, the spikemosses or lesser clubmosses. This family is distinguished from Lycopodiaceae (the clubmosses) by having scale-leaves bearing a ligule and by having ...

'') to be a clade that is sister to all other ''Selaginellas'', so any definitive subdivision of the species into separate genera leaves two taxa in ''Selaginella'', with the hundreds of other species in new or resurrected genera. ''Selaginella'' occurs mostly in the tropical regions of the world, with a handful of species to be found in the arctic-alpine zones of both hemispheres.

Description

''Selaginella'' species are creeping or ascendant plants with simple, scale-like leaves ( microphylls) on branching stems from which roots also arise. The stems are aerial, horizontally creeping on the substratum (as in ''

Selaginella kraussiana ''Selaginella kraussiana'' is a species of vascular plant in the family Selaginellaceae. It is referred to by the common names Krauss' spikemoss, Krauss's clubmoss, or African clubmoss, and is found naturally in parts of Sub-Saharan Africa and ...

''), sub-erect (''

Selaginella trachyphylla ''Selaginella'' is the sole genus of vascular plants in the family Selaginellaceae, the spikemosses or lesser clubmosses. This family is distinguished from Lycopodiaceae (the clubmosses) by having scale-leaves bearing a ligule and by having ...

'') or erect (as in ''

Selaginella erythropus ''Selaginella erythropus'' is a species of plant in the Selaginellaceae family, endemic to the Yucatan and Belize to Colombia Colombia (, ; ), officially the Republic of Colombia, is a country in South America with insular regions in ...

''). The vascular

steles A stele ( ),Anglicized plural steles ( ); Greek plural stelai ( ), from Greek , ''stēlē''. The Greek plural is written , ''stēlai'', but this is only rarely encountered in English. or occasionally stela (plural ''stelas'' or ''stelæ''), whe ...

are polystelic protosteles. Stem section shows the presence of more than two protosteles. Each stele is made up of diarch (having two strands of xylem) and

exarch An exarch (; from Ancient Greek ἔξαρχος ''exarchos'', meaning “leader”) was the holder of any of various historical offices, some of them being political or military and others being ecclesiastical. In the late Roman Empire and ea ...

(growing outward in)

xylem Xylem is one of the two types of transport tissue in vascular plants, the other being phloem. The basic function of xylem is to transport water from roots to stems and leaves, but it also transports nutrients. The word ''xylem'' is derived fr ...

s. The steles are connected with the cortex by means of many tube-like structures called

trabeculae A trabecula (plural trabeculae, from Latin for "small beam") is a small, often microscopic, tissue element in the form of a small beam, strut or rod that supports or anchors a framework of parts within a body or organ. A trabecula generally has ...

, which are modified endodermal cells with casparian strips on their lateral walls. The stems contain no pith. In ''Selaginella'', each microphyll and sporophyll has a small scale-like outgrowth called a

ligule A ligule (from "strap", variant of ''lingula'', from ''lingua'' "tongue") is a thin outgrowth at the junction of leaf and leafstalk of many grasses (Poaceae) and sedges. A ligule is also a strap-shaped extension of the corolla, such as that of a ...

at the base of the upper surface. The plants are

heterosporous Heterospory is the production of spores of two different sizes and sexes by the sporophytes of land plants. The smaller of these, the microspore, is male and the larger megaspore is female. Heterospory evolved during the Devonian period from i ...

with spores of two different size classes, known as megaspores and microspores. Unusual for the lycopods, which nearly always have microphylls with a single unbranched vein, the microphylls of a few ''Selaginella'' species contain a branched vascular trace. Under dry conditions, some species of ''Selaginella'' can survive dehydration. In this state, they may roll up into brown balls and be uprooted, but can rehydrate under moist conditions, become green again and resume growth. This phenomenon is known as

poikilohydry Poikilohydry is the lack of ability (structural or functional mechanism) to maintain and/or regulate water content to achieve homeostasis In biology, homeostasis ( British also homoeostasis) (/hɒmɪə(ʊ)ˈsteɪsɪs/) is the state of steady i ...

, and poikilohydric plants such as ''Selaginella bryopteris'' are sometimes referred to as resurrection plants.

Taxonomy

Some scientists still place the Selaginellales in the class

Lycopodiopsida Lycopodiopsida is a class of vascular plants known as lycopods, lycophytes or other terms including the component lyco-. Members of the class are also called clubmosses, firmosses, spikemosses and quillworts. They have dichotomously branching s ...

(often misconstructed as "Lycopsida"). Some modern authors recognize three generic divisions of ''Selaginella'': ''Selaginella'', ''Bryodesma'' Sojak 1992, and ''Lycopodioides'' Boehm 1760. ''Lycopodioides'' would include the North American species ''S. apoda'' and ''S. eclipes'', while ''Bryodesma'' would include ''S. rupestris'' (as ''Bryodesma rupestre''). ''Stachygynandrum'' is also sometimes used to include the bulk of species. The first major attempt to define and subdivide the group was by Palisot de Beauvois in 1803-1805. He established the genus ''Selaginella'' as a monotypic genus, and placed the bulk of species in ''Stachygynandrum''. ''Gymnogynum'' was another monotypic genus, but that name is superseded by his own earlier name of ''Didiclis''. This turns out, today, to be a group of around 45-50 species also known as the ''Articulatae'', since his genus ''Didiclis/Gymnogynum'' was based on ''

Selaginella plumosa ''Selaginella'' is the sole genus of vascular plants in the family Selaginellaceae, the spikemosses or lesser clubmosses. This family is distinguished from Lycopodiaceae (the clubmosses) by having scale-leaves bearing a ligule and by having ...

''. He also described the genus ''Diplostachyum'' to include a group of species similar to ''Selaginella apoda''. Spring inflated the genus ''Selaginella'' to hold all selaginelloid species four decades later. Phylogenetic studies by Korall & Kenrick determined that the ''Euselaginella'' group, comprising solely the type species, '' Selaginella selaginoides'' and a closely related Hawaiian species, ''

'', is a basal and anciently diverging sister to all other ''Selaginella'' species. Beyond this, their study split the remainder of species into two broad groups, one including the '' Bryodesma'' species, the '' Articulatae'', section '' Ericetorum'' Jermy and others, and the other centered on the broad ''Stachygynandrum'' group.

Walton & Aston classification

In the ''Manual of Pteridology'', the following classification was used by Walton & Alston: genus: ''Selaginella'' *subgenus: ''Euselaginella'' **group: ''selaginoides'' **group: ''pygmaea'' **group: ''uliginosa'' (''Ericetorum'') **group: ''rupestris'' (''Tetragonostachys'' or ''Bryodesma'') *subgenus: ''Stachygynandrum'' **series: ''Decumbentes'' **series: ''Ascendentes'' **series: ''Sarmentosae'' **series: ''Caulescentes'' **series: ''Circinatae'' **series: ''Articulatae'' *subgenus: ''Homostachys'' *subgenus: ''Heterostachys'' However, this is now known to be highly paraphyletic in most of its groupings. Two recent classifications, employing modern methods of phylogenetic analysis, are as follows:

Weststrand & Korall, 2016 classification

genus: ''Selaginella'' * subgenus: ''Selaginella'' * clade: "Rhizophoric clade" ** clade A *** subgenus ''Rupestrae'' 'Bryodesma'' Sojak or ''Tetragonostachys'' Jermy, ''S.'' section ''Homeophyllae''*** subgenus ''Lepidophyllae'' 'S.'' section ''Lepidophyllae''*** subgenus ''Gymnogynum'' 'S.'' section ''Articulatae''*** subgenus ''Exaltatae'' ncl. ''S.'' section ''Megalosporum'', ''S.'' section ''Myosurus''*** subgenus ''Ericetorum'' 'S.'' section ''Lyallia''** clade B *** subgenus ''Stachygynandrum'' ncl. ''S.'' (''Boreoselaginella''), ''S.'' (''Pulviniella''), ''S.'' (''Heterostachys'')

Zhang & Zhou, 2015 classification

genus: ''Selaginella'' * subgenus: ''Selaginella'' Type: ''S. selaginoides'' (L.) P.Beauv. ex Mart. & Schrank * subgenus: ''Boreoselaginella'' Type: ''S. sanguinolenta'' (L.) Spring * subgenus: ''Ericetorum'' Type: ''S. uliginosa'' (Labill.) Spring ** section: ''Lyallia'' Type: ''S. uliginosa'' (Labill.) Spring ** section: ''Myosurus'' Type: ''S. myosurus'' Alston ** section: ''Megalosporarum'' Type: ''S. exaltata'' (Kunze) Spring ** section: ''Articulatae'' Type: ''S. kraussiana'' (Kunze) A.Braun ** section: ''Homoeophyllae'' Type: ''S. rupestris'' (L.) Spring (=''Bryodesma'' Sojak or ''Tetragonostachys'' Jermy) ** section: ''Lepidophyllae'' Type: ''S. lepidophylla'' (Hook. & Grev.) Spring * subgenus: ''Pulviniella'' Type: ''S. pulvinata'' (Hook. & Grev.) Maxim * subgenus: ''Heterostachys'' Type: ''S. heterostachys'' Baker ** section: ''Oligomacrosporangiatae'' Type: ''Selaginella uncinata'' (Desv. ex Poir.) Spring ** section: ''Auriculatae'' Type: ''S. douglasii'' (Hook. & Grev.) Spring ** section: ''Homostachys'' Type: : ''S. helvetica'' (L.) Link ** section: ''Tetragonostachyae'' Type: ''S. proniflora'' (L.) Baker ** section: ''Heterostachys'' Type: ''S. brachystachya'' (Hook. & Grev.) Spring * subgenus: ''Stachygynandrum'' Type: ''S. flabellata'' (L.) Spring ** section: ''Plagiophyllae'' Type: ''S. biformis'' A.Braun ex Kuhn ** section: ''Circinatae'' Type: ''S. involvens'' (Sw.) Spring ** section: ''Heterophyllae'' Type: ''S. flexuosa'' Spring ** section: ''Austroamericanae'' Type: ''S. hartwegiana'' Spring ** section: ''Pallescentes'' Type: ''S. pallescens'' (C.Presl) Spring ** section: ''Proceres'' Type: ''S. oaxacana'' Spring ** section: ''Ascendentes'' Type: ''S. alopecuroides'' Baker

Species

Selaginella selaginoides - Niitvälja bog

There are about 750 known species of ''Selaginella''. They show a wide range of characters; the genus is overdue for a revision which might include subdivision into several genera. Better-known spikemosses include: *''

Selaginella apoda ''Selaginella apoda'', commonly known as meadow spikemoss, is a perennial lycophyte native to much of the eastern United States and parts of northeastern Mexico. The life cycle is the shortest of the genus ''Selaginella'', as well as one of the s ...

'' – meadow spikemoss; eastern

North America North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and the C ...

*'' Selaginella arizonica'' Maxon – west Texas to Arizona and Sonora, Mexico *'' Selaginella asprella'' *'' Selaginella bifida'' –

Rodrigues Island Rodrigues (french: Île Rodrigues, link=yes ; Creole: ) is a autonomous outer island of the Republic of Mauritius in the Indian Ocean, about east of Mauritius. It is part of the Mascarene Islands, which include Mauritius and Réunion. Rodr ...

*'' Selaginella biformis'' *'' Selaginella bigelovii'' *'' Selaginella braunii'' – Braun's spikemoss;

China China, officially the People's Republic of China (PRC), is a country in East Asia. It is the world's List of countries and dependencies by population, most populous country, with a Population of China, population exceeding 1.4 billion, slig ...

*'' Selaginella bryopteris'' – sanjeevani;

India India, officially the Republic of India ( Hindi: ), is a country in South Asia. It is the seventh-largest country by area, the second-most populous country, and the most populous democracy in the world. Bounded by the Indian Ocean on the ...

*'' Selaginella canaliculata'' – clubmoss;

southeast Asia Southeast Asia, also spelled South East Asia and South-East Asia, and also known as Southeastern Asia, South-eastern Asia or SEA, is the geographical south-eastern region of Asia, consisting of the regions that are situated south of mainland ...

Maluku Islands The Maluku Islands (; Indonesian: ''Kepulauan Maluku'') or the Moluccas () are an archipelago in the east of Indonesia. Tectonically they are located on the Halmahera Plate within the Molucca Sea Collision Zone. Geographically they are located ...

*'' Selaginella carinata'' *'' Selaginella cinerascens'' *'' Selaginella densa'' – lesser spikemoss; western North America *'' Selaginella denticulata'' *'' Selaginella eclipes'' – hidden spikemoss; eastern North America *'' Selaginella elmeri'' *'' Selaginella eremophila'' Maxon *''

'' *'' Selaginella galotteii'' *'' Selaginella gigantea'' - From Venezuela. *'' Selaginella hansenii'' *''

'' – Krauss's spikemoss;

Africa Africa is the world's second-largest and second-most populous continent, after Asia in both cases. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 6% of Earth's total surface area ...

Azores ) , motto =( en, "Rather die free than subjected in peace") , anthem= ( en, "Anthem of the Azores") , image_map=Locator_map_of_Azores_in_EU.svg , map_alt=Location of the Azores within the European Union , map_caption=Location of the Azores wi ...

*'' Selaginella lepidophylla'' – resurrection plant, dinosaur plant, and flower of stone;

Chihuahuan Desert The Chihuahuan Desert ( es, Desierto de Chihuahua, ) is a desert ecoregion designation covering parts of northern Mexico and the southwestern United States. It occupies much of far West Texas, the middle to lower Rio Grande Valley and the lower ...

*'' Selaginella martensii'' – variegated spikemoss *''

Selaginella moellendorffii ''Selaginella moellendorffii'' is a lycophyte that is an important model organism, especially in comparative genomics. ''S. moellendorffii'' is a member of an ancient vascular plant lineage that first appeared in the fossil record some 400 mill ...

'' *'' Selaginella oregana'' *'' Selaginella plana'' – Asian spikemoss; tropical

Asia Asia (, ) is one of the world's most notable geographical regions, which is either considered a continent in its own right or a subcontinent of Eurasia, which shares the continental landmass of Afro-Eurasia with Africa. Asia covers an area ...

*'' Selaginella poulteri'' *'' Selaginella pulcherrima'' *'' Selaginella rupestris'' – rock spikemoss, festoon pine, and northern Selaginella (eastern North America) *'' Selaginella rupincola'' Underw. – west Texas to Arizona and Sonora, Mexico *'' Selaginella selaginoides'' – lesser clubmoss; north temperate

Europe Europe is a large peninsula conventionally considered a continent in its own right because of its great physical size and the weight of its history and traditions. Europe is also considered a Continent#Subcontinents, subcontinent of Eurasia ...

and

) *'' Selaginella sericea'' A.Braun –

Ecuador Ecuador ( ; ; Quechuan languages, Quechua: ''Ikwayur''; Shuar language, Shuar: ''Ecuador'' or ''Ekuatur''), officially the Republic of Ecuador ( es, República del Ecuador, which literally translates as "Republic of the Equator"; Quechuan ...

*'' Selaginella serpens'' *'' Selaginella sibirica'' *'' Selaginella stellata'' – starry spikemoss; Mexico,

Central America Central America ( es, América Central or ) is a subregion of the Americas. Its boundaries are defined as bordering the United States to the north, Colombia to the south, the Caribbean Sea to the east, and the Pacific Ocean to the west. ...

*'' Selaginella substipitata'' *'' Selaginella tamariscina'' *'' Selaginella tortipila'' *'' Selaginella uliginosa'' –

Australia Australia, officially the Commonwealth of Australia, is a sovereign country comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands. With an area of , Australia is the largest country b ...

*'' Selaginella umbrosa'' *'' Selaginella uncinata'' – peacock moss, peacock spikemoss, blue spikemoss *'' Selaginella underwoodii'' Hieron. – west Texas to Wyoming and west into Arizona *'' Selaginella wallacei'' *'' Selaginella watsonii'' *'' Selaginella willdenowii'' – Willdenow's spikemoss, peacock fern; southeast Asia A few species of ''Selaginella'' are

desert A desert is a barren area of landscape where little precipitation occurs and, consequently, living conditions are hostile for plant and animal life. The lack of vegetation exposes the unprotected surface of the ground to denudation. About one ...

plants known as "resurrection plants", because they curl up in a tight, brown or reddish ball during dry times, and uncurl and turn green in the presence of moisture. Other species are tropical

forest A forest is an area of land dominated by trees. Hundreds of definitions of forest are used throughout the world, incorporating factors such as tree density, tree height, land use, legal standing, and ecological function. The United Nations' ...

plants that appear at first glance to be

fern A fern (Polypodiopsida or Polypodiophyta ) is a member of a group of vascular plants (plants with xylem and phloem) that reproduce via spores and have neither seeds nor flowers. The polypodiophytes include all living pteridophytes except t ...

Cultivation

A number of ''Selaginella'' species are popular plants for cultivation, mostly tropical species. Some of the species popularly cultivated and actively available commercially include: *''S. kraussiana'': golden clubmoss *''S. martensii'': frosty fern *''S. moellendorffii'': gemmiferous spikemoss *''S. erythropus'': red selaginella or ruby-red spikemoss *''S. uncinata'': peacock moss *''S. lepidophylla'': resurrection plant *''S. braunii'': arborvitae fern

References

External links

* * {{Taxonbar, from=Q379743 Lycophyte genera