Lycopodiaceae (Clubmosses) | |
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Spinulum annotinum | |
Scientific classification | |
Kingdom: | Plantae |
Clade: | Tracheophytes |
Clade: | Lycophytes |
Class: | Lycopodiopsida |
Order: | Lycopodiales |
Family: | Lycopodiaceae P.Beauv. ex Mirb. 1802 [1] |
Genera | |
See text |
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 [2] and about 400 known species. [3] This family originated about 380 million years ago in the early Devonian, though the diversity within the family has been much more recent. [4] "Wolf foot" is another common name for this family due to the resemblance of either the roots or branch tips to a wolf's paw. [5]
Members of Lycopodiaceae are not spermatophytes and so do not produce seeds. Instead they produce spores, which are oily and flammable, and are the most economically important aspects of these plants. The spores are of one size (i.e. the plants are isosporous) and are borne on a specialized structure at the apex of a shoot called a strobilus (plural: strobili), which resembles a tiny battle club, from which the common name derives. Members of the family share the common feature of having a microphyll, which is a "small leaf with a single vein, and not associated with a leaf gap in the central vascular system." [4] In Lycopodiaceae, the microphylls often densely cover the stem in a linear, scale-like, or appressed fashion to the stem, and the leaves are either opposite or spirally arranged. The club mosses commonly grow to be 5–20 cm tall. [4] The gametophytes in most species are non-photosynthetic and myco-heterotrophic, but the subfamily Lycopodielloideae and a few species in the subfamily Huperzioideae have gametophytes with an upper green and photosynthetic part, and a colorless lower part in contact with fungal hyphae. [6] [7] In Lycopodioideae monoplastidic meiosis is common, whereas polyplastidic meiosis is found in Lycopodielloideae and Huperzioideae. [8]
The family Lycopodiaceae is considered to be basal within the Lycopodiopsida (lycophytes). One hypothesis for the evolutionary relationships involved is shown in the cladogram below. [2]
Lycopodiopsida |
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Within the family, there is support for three subgroups. In 2016, Field et al. proposed that the primary division is between Lycopodielloideae plus Lycopodioideae and the Huperzioideae (names sensu PPG I). [9]
Lycopodiaceae |
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There are about 400 known species in the family Lycopodiaceae. [3] Sources differ in how they group these into genera. Field et al. (2016) say "Most Lycopodiaceae species have been re-classified into different genera several times, leading to uncertainty about their most appropriate generic identification." [9] In the PPG I system, the family has 16 accepted genera, grouped into three subfamilies, Lycopodielloideae, Lycopodioideae and Huperzioideae, based in part on molecular phylogenetic studies. The Huperzioideae differ in producing spores in small lateral structures in the leaf axils, [9] and it has been suggested that they be recognized as a separate family.[ citation needed ] Other sources use fewer genera; for example, the three genera placed in the subfamily Huperzioideae in PPG I, Huperzia , Phlegmariurus and Phylloglossum , have also all been treated within a broadly defined Huperzia. [9]
The species within this family generally have chromosome counts of n=34. A notable exception are the species in Diphasiastrum , which have counts of n=23. [10]
As of June 2024 [update] , the Checklist of Ferns and Lycophytes of the World recognized the following genera as members of Lycopodiaceae. [11] All of these are recognized by the Pteridophyte Phylogeny Group classification of 2016 (PPG I), except for the genus Brownseya, described in 2021. [2] Other classifications circumscribe the genera in the family more broadly, recognizing the subfamilies Lycopodielloideae, Lycopodioideae, and Huperzioideae as the genera Lycopodiella, Lycopodium, and Huperzia.
The members of Lycopodiaceae are terrestrial or epiphytic in habit and are most prevalent in tropical mountain and alpine environments. [4] Though Lycopodiaceae are most abundant in these regions, they are cosmopolitan, excluding arid environments. [12]
Lycopodiaceae (homosporous lycophytes) split off from the branch leading to Selaginella and Isoetes (heterosporous lycophytes) about ~400 million years ago, during the early Devonian. The two subfamilies Lycopodioideae and Huperzioideae diverged ~350 million years ago, but has evolved so slowly that about 30% of their genes are still in syntenic blocks (remaining in the same arrangement). They have also gone through independent whole genome duplications. In most plants the majority of duplicate genes are lost relatively quickly through diploidization, but in this group both sets of genes tends to be retained with relatively few alterations, even after hundreds of millions of years after the duplication event. [13] [14] Spores indicate that the crown group of Lycopodiaceae had emerged by the Triassic-Jurassic boundary, around 200 million years ago, [15] with a member of the crown group of Lycopodioideae known from the Early Cretaceous of China. [16]
Lycopodiopsida is a class of vascular plants also known as lycopods or lycophytes. Members of the class are also called clubmosses, firmosses, spikemosses and quillworts. They have dichotomously branching stems bearing simple leaves called microphylls and reproduce by means of spores borne in sporangia on the sides of the stems at the bases of the leaves. Although living species are small, during the Carboniferous, extinct tree-like forms (Lepidodendrales) formed huge forests that dominated the landscape and contributed to coal deposits.
The lycophytes, when broadly circumscribed, are a group of vascular plants that include the clubmosses. They are sometimes placed in a division Lycopodiophyta or Lycophyta or in a subdivision Lycopodiophytina. They are one of the oldest lineages of extant (living) vascular plants; the group contains extinct plants that have been dated from the Silurian. Lycophytes were some of the dominating plant species of the Carboniferous period, and included the tree-like Lepidodendrales, some of which grew over 40 metres (130 ft) in height, although extant lycophytes are relatively small plants.
Huperzia is a genus of lycophyte plants, sometimes known as the firmosses or fir clubmosses; the Flora of North America calls them gemma fir-mosses. This genus was originally included in the related genus Lycopodium, from which it differs in having undifferentiated sporangial leaves, and the sporangia not formed into apical cones. The common name firmoss, used for some of the north temperate species, refers to their superficial resemblance to branches of fir (Abies), a conifer. As of 2020, two very different circumscriptions of the genus were in use. In the Pteridophyte Phylogeny Group classification of 2016, Huperzia is one of three genera in the subfamily Huperzioideae of the family Lycopodiaceae. Most species in the subfamily are placed in the genus Phlegmariurus. Huperzia is left with about 25 species, although not all have been formally transferred to other genera. Other sources recognize only Huperzia, which then has about 340 species.
Huperzioideae is a subfamily of lycopsids in the family Lycopodiaceae. It has sometimes been recognized as a separate family, Huperziaceae. The Pteridophyte Phylogeny Group classification of 2016 recognizes three extant genera:
Lycopodium is a genus of clubmosses, also known as ground pines or creeping cedars, in the family Lycopodiaceae. Two very different circumscriptions of the genus are in use. In the Pteridophyte Phylogeny Group classification of 2016, Lycopodium is one of nine genera in the subfamily Lycopodioideae, and has from nine to 15 species. In other classifications, the genus is equivalent to the whole of the subfamily, since it includes all of the other genera. More than 40 species are accepted.
Diphasiastrum is a genus of clubmosses in the plant family Lycopodiaceae. In the Pteridophyte Phylogeny Group classification of 2016, it is placed in the subfamily Lycopodioideae. It is closely related to the genus Lycopodium, and some botanists treat it within a broad view of that genus as a section, Lycopodium sect. Complanata. Some species superficially resemble diminutive gymnosperms and have been given common names such as ground-pine or ground-cedar.
Lycopodiella is a genus in the clubmoss family Lycopodiaceae. The genus members are commonly called bog clubmosses, describing their wetland habitat. The genus has a cosmopolitan distribution, with centers of diversity in the tropical New World and New Guinea. In the past, the genus was often incorporated within the related genus Lycopodium, but was segregated in 1964. In the Pteridophyte Phylogeny Group classification of 2016, Lycopodiella is placed in the subfamily Lycopodielloideae, along with three other genera. In this circumscription, the genus has about 15 species. Other sources use a wider circumscription, in which the genus is equivalent to the Lycopodielloideae of PPG I, in which case about 40 species and hybrids are accepted.
Phlegmariurus phlegmaria, synonym Huperzia phlegmaria, commonly known as either coarse tassel fern or common tassel fern, is an epiphytic species native to rainforests in Madagascar, some islands in the Indian Ocean, Asia, Australasia and many Pacific Islands. Phlegmariurus phlegmaria is commonly found in moist forests and rainforests at high altitudes, in and amongst mosses and other epiphytes. Members of the order Lycopodiales are commonly referred to as clubmosses.
Pseudolycopodiella is a genus of non-seed plants in the Lycopodiaceae, long considered part of Lycopodium, but now recognized as a separate genus. It has 10–14 recognized species, only one in North America: Pseudolycopodiella caroliniana.
The Pteridophyte Phylogeny Group (PPG) is an informal international group of systematic botanists who collaborate to establish a consensus on the classification of pteridophytes that reflects knowledge about plant relationships discovered through phylogenetic studies. In 2016, the group published a classification for extant pteridophytes, termed "PPG I". The paper had 94 authors.
Lateristachys is a genus of lycophytes in the family Lycopodiaceae. In the Pteridophyte Phylogeny Group classification of 2016, it is placed in the subfamily Lycopodielloideae. Some sources do not recognize the genus, sinking it into Lycopodiella. Lateristachys species are native to the Philippines, Australia and New Zealand.
Palhinhaea is a genus of lycophytes in the family Lycopodiaceae. In the Pteridophyte Phylogeny Group classification of 2016, it is placed in the subfamily Lycopodielloideae. Some sources do not recognize the genus, sinking it into Lycopodiella. Palhinhaea species are widespread in the tropics and subtropics.
Austrolycopodium is a genus of lycophytes in the family Lycopodiaceae. In the Pteridophyte Phylogeny Group classification of 2016, it is placed in the subfamily Lycopodioideae. Some sources do not recognize the genus, sinking it into Lycopodium. Austrolycopodium species are mostly native to the temperate southern hemisphere.
Diphasium is a genus of lycophytes in the family Lycopodiaceae. In the Pteridophyte Phylogeny Group classification of 2016, it is placed in the subfamily Lycopodioideae. Some sources do not recognize the genus, sinking it into Lycopodium, others include it in Diphasiastrum. Diphasium species are mostly native to the temperate southern hemisphere, but extend northwards into Central America and the Caribbean.
Lycopodiastrum is a genus of lycophyte in the family Lycopodiaceae with only one species, Lycopodiastrum casuarinoides. In the Pteridophyte Phylogeny Group classification of 2016, the genus is placed in the subfamily Lycopodioideae. Some sources do not recognize the genus, sinking it into Lycopodium. Lycopodiastrum casuarinoides is native to south-eastern Asia, from Tibet through China to Japan in the north, and from Sumatra to Sulawesi in the south.
Pseudodiphasium is a genus of lycophyte in the family Lycopodiaceae with only one species, Pseudodiphasium volubile. In the Pteridophyte Phylogeny Group classification of 2016, the genus is placed in the subfamily Lycopodioideae. Some sources do not recognize the genus, sinking it into Lycopodium. Pseudodiphasium volubile is native from Peninsular Malaysia to Queensland, Australia, and has been introduced into Ecuador.
Pseudolycopodium is a genus of lycophyte in the family Lycopodiaceae with only one species, Pseudolycopodium densum, known as the bushy clubmoss. In the Pteridophyte Phylogeny Group classification of 2016, the genus is placed in the subfamily Lycopodioideae. Some sources do not recognize the genus, sinking it into Lycopodium. Pseudolycopodium densum is native to Australia, the North Island of New Zealand and New Caledonia. It is a spore-bearing vascular plant and grows up to a metre high. It is found in a wide variety of situations, often in high rainfall areas on sandy soils.
Lycopodioideae is a subfamily in the family Lycopodiaceae in the Pteridophyte Phylogeny Group classification of 2016. It is equivalent to a broad circumscription of the genus Lycopodium in other classifications. Like all lycophytes, members of the Lycopodioideae reproduce by spores. The oldest fossils of modern members of the subfamily date to the Early Cretaceous.
Lycopodielloideae is a subfamily in the family Lycopodiaceae in the Pteridophyte Phylogeny Group classification of 2016. It is equivalent to a broad circumscription of the genus Lycopodiella in other classifications. Like all lycophytes, members of the Lycopodielloideae are vascular plants that reproduce by spores.