lycophytes and ferns were the first land plants to have what feature?

Broadly confining group of spore bearing plants

This article is about a broadly divers group of plants that includes the extinct zosterophylls. For the grouping excluding the zosterophylls, encounter Lycopodiopsida.

Lycophyte Temporal range: 428–0 Ma PreꞒ Ꞓ O S D C P T J M Pg Northward Silurian[1] to contempo
Reconstruction of a Lepidodendron establish
Scientific classification
Kingdom:	Plantae
Clade:	Tracheophytes
Clade:	Lycophytes
Classes
Lycopodiopsida - clubmosses, spikemosses, quillworts, scale copse †Zosterophyllopsida - zosterophylls

The lycophytes, when broadly confining, are a vascular found (tracheophyte) subgroup of the kingdom Plantae. They are sometimes placed in a partition 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 (ca. 425 1000000 years ago).^{[2] [3]} Lycophytes were some of the dominating constitute species of the Carboniferous period, and included tree-like species, although extant lycophytes are relatively small plants.^[four]

The scientific names and the informal English names used for this group of plants are ambiguous. For example, "Lycopodiophyta" and the shorter "Lycophyta" as well as the breezy "lycophyte" may be used to include the extinct zosterophylls or to exclude them.

Clarification [edit]

Lycophytes reproduce past spores and have alternation of generations in which (like other vascular plants) the sporophyte generation is dominant. Some lycophytes are homosporous while others are heterosporous.^[five] When broadly circumscribed, the lycophytes represent a line of evolution distinct from that leading to all other vascular plants, the euphyllophytes, such as ferns, gymnosperms and flowering plants. They are defined by two synapomorphies: lateral rather than terminal sporangia (frequently kidney-shaped or reniform), and exarch protosteles, in which the protoxylem is exterior the metaxylem rather than vice versa. The extinct zosterophylls have at most only flap-similar extensions of the stalk ("enations") rather than leaves, whereas extant lycophyte species accept microphylls, leaves that have only a single vascular trace (vein), rather than the much more complex megaphylls of other vascular plants. The extinct genus Asteroxylon represents a transition between these two groups: it has a vascular trace leaving the central protostele, only this extends merely to the base of the enation.^[six] See § Evolution of microphylls.

Zosterophylls and extant lycophytes are all relatively pocket-size plants, but some extinct species, such as the Lepidodendrales, were tree-like, and formed all-encompassing forests that dominated the landscape and contributed to the formation of coal.^[six]

Taxonomy [edit]

Classification [edit]

In the broadest circumscription of the lycophytes, the group includes the extinct zosterophylls every bit well as the extant (living) lycophytes and their closest extinct relatives. The names and ranks used for this group vary considerably. Some sources employ the names "Lycopodiophyta" or the shorter "Lycophyta" to include zosterophylls likewise as extant lycophytes and their closest extinct relatives,^[vii] while others apply these names to exclude zosterophylls.^{[viii] [half-dozen]} The name "Lycopodiophytina" has also been used in the inclusive sense.^{[ix] [10]} English language names, such as "lycophyte", "lycopodiophyte" or "lycopod", are similarly cryptic, and may refer to the broadly defined group or only to the extant lycophytes and their closest extinct relatives.

The consensus classification produced by the Pteridophyte Phylogeny Group nomenclature in 2016 (PPG I) places all extant (living) lycophytes in the class Lycopodiopsida.^[11] There are around one,290 to 1,340 such species.^{[12] [13] [11]} For more information on the nomenclature of extant lycophytes, see Lycopodiopsida § Classification.

Phylogeny [edit]

A major cladistic report of state plants was published in 1997 by Kenrick and Crane.^[1] In 2004, Crane et al. published some simplified cladograms, based on a number of figures in Kenrick and Crane (1997). Their cladogram for the lycophytes is reproduced beneath (with some branches collapsed into 'basal groups' to reduce the size of the diagram).^[14]

† basal groups (Cooksonia cambrensis, Renalia, Sartilmania, Uskiella, Yunia) lycophytes †Hicklingia †basal groups (Adoketophyton, Discalis, Distichophytum (=Rebuchia), Gumuia, Huia, Zosterophyllum myretonianum, Z. llanoveranum, Z. fertile) †'cadre' zosterophylls (Zosterophyllum divaricatum, Tarella, Oricilla, Gosslingia, Hsua, Thrinkophyton, Protobarinophyton, Barinophyton obscurum, B. citrulliforme, Sawdonia, Deheubarthia, Konioria, Anisophyton, Serrulacaulis, Crenaticaulis)

In this view, the "zosterophylls" contain a paraphyletic grouping, ranging from forms similar Hicklingia, which had bare stems,^[15] to forms like Sawdonia and Nothia, whose stems are covered with unvascularized spines or enations.^{[16] [17]} The genus Renalia illustrates the problems in classifying early land plants. It has characteristics both of the non-lycophyte rhyniophytes – terminal rather than lateral sporangia – and of the zosterophylls – kidney-shaped sporangia opening along the distal margin.^[18]

A rather different view is presented in a 2013 analysis past Hao and Xue. Their preferred cladogram shows the zosterophylls and associated genera basal to both the lycopodiopsids and the euphyllophytes, so that there is no clade corresponding to the broadly divers group of lycophytes used by other authors.^[nineteen]

"lycophytes" of other authors

Some extinct orders of lycophytes fall into the same group as the extant orders. Unlike sources utilise varying numbers and names of the extinct orders. The following phylogram shows a likely relationship between some of the proposed Lycopodiopsida orders.^{[ citation needed ]}

Evolution of microphylls [edit]

Within the broadly divers lycophyte group, species placed in the grade Lycopodiopsida are distinguished from species placed in the Zosterophyllopsida by the possession of microphylls. Some zosterophylls, such as the Devonian Zosterophyllum myretonianum, had smooth stems (axes). Others, such as Sawdonia ornata, had flap-like extensions on the stems ("enations"), only without any vascular tissue. Asteroxylon, identified every bit an early lycopodiopsid, had vascular traces that extended to the base of operations of the enations. Species in the genus Leclercqia had fully vascularized microphylls. These are considered to be stages in the evolution of microphylls.^[twenty]

Gallery [edit]

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  Lycopodites, an early lycopod-like fossil

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  Lycopod bark showing leafage scars, from the Centre Devonian of Wisconsin.

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  Lycopod axis (branch) from the Middle Devonian of Wisconsin.

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  Restoration of Pleuromeia, an extinct Isoetales genus from the Early Triassic

References [edit]

1. ^ ^{a b} Kenrick, Paul; Crane, Peter R. (1997). The Origin and Early Diversification of State Plants: A Cladistic Study. Washington, D. C.: Smithsonian Institution Press. pp. 339–340. ISBN978-1-56098-730-seven.
2. ^ Rickards, R.B. (2000). "The age of the earliest lodge mosses: the Silurian Baragwanathia flora in Victoria, Commonwealth of australia". Geological Magazine. 137 (2): 207–209. Bibcode:2000GeoM..137..207R. doi:x.1017/s0016756800003800. S2CID 131287538.
3. ^ McElwain, Jenny C.; Willis, K. 1000.; Willis, Kathy; McElwain, J. C. (2002). The development of plants. Oxford [Oxfordshire]: Oxford University Press. ISBN978-0-xix-850065-0.
4. ^ Ranker, T. A.; Hauler, C. H. (2008). Biology and evolution of ferns and lycophytes. Cambridge: Cambridge University Press.
5. ^ Eichhorn, Evert, and Raven (2005). Biology of Plants, Seventh Edition. 381-388.
6. ^ ^{a b c} Mauseth, James D. (2014). Botany : An introduction to Plant Biology (5th ed.). Burlington, MA: Jones & Bartlett Learning. ISBN978-1-4496-6580-7.
7. ^ Doweld, Alexander B. (2017). "(2499) Proposal to conserve the proper noun Zosterophyllaceae against Sciadophytaceae (Fossil Lycopodiophyta: Zosterophyllopsida)". Taxon. 66 (1): 207–208. doi:ten.12705/661.27.
8. ^ Taylor, T.N.; Taylor, E.L. & Krings, K. (2009). Paleobotany : The Biology and Evolution of Fossil Plants (2nd ed.). Amsterdam; Boston: Academic Press. ISBN978-0-12-373972-viii.
9. ^ Kenrick, Paul & Crane, Peter R. (1997a). The Origin and Early Diversification of Land Plants: A Cladistic Study. Washington, D.C.: Smithsonian Institution Press. ISBN978-one-56098-730-seven.
10. ^ Kenrick, Paul & Crane, Peter R. (1997b). "The origin and early evolution of plants on land". Nature. 389 (6646): 33–39. Bibcode:1997Natur.389...33K. doi:x.1038/37918. S2CID 3866183.
11. ^ ^{a b} PPG I (2016). "A community-derived nomenclature for extant lycophytes and ferns". Journal of Systematics and Evolution. 54 (6): 563–603. doi:10.1111/jse.12229. S2CID 39980610.
12. ^ Unconversant, R.S. & Melt, Laurence Martin (1999). Genetic and evolutionary diversity: the sport of nature. Cheltenham: S. Thornes. p. 8. ISBN978-0-7487-4336-0.
13. ^ Christenhusz, M. J. M., M.J.M. & Byng, J.W. (2016). "The number of known plants species in the world and its annual increment". Phytotaxa. 261 (3): 201–217. doi:10.11646/phytotaxa.261.3.1.
14. ^ Crane, P.R.; Herendeen, P. & Friis, E.M. (2004). "Fossils and plant phylogeny". American Journal of Botany. 91 (ten): 1683–1699. doi:10.3732/ajb.91.ten.1683. PMID 21652317. S2CID 8493380.
15. ^ Edwards, D. (1976). "The systematic position of Hicklingia edwardii Kidston and Lang". New Phytologist. 76: 173–181. doi:x.1111/j.1469-8137.1976.tb01449.x.
16. ^ Taylor, Taylor & Krings (2009), p. 253.
17. ^ Kerp, H.; Hass, M.H. & Mosbrugger, V. (2001). "New Data on Nothia aphylla Lyon 1964 ex El-Saadawy et Lacey 1979, a Poorly Known Constitute from the Lower Devonian Rhynie Chert". In Gensel, P.1000. & Edwards, D. (eds.). Plants invade the Land : Evolutionary & Ecology Perspectives. New York: Columbia University Press. pp. 52–82. ISBN978-0-231-11161-iv.
18. ^ Taylor, Taylor & Krings (2009), p. 250.
19. ^ Hao, Shougang & Xue, Jinzhuang (2013). The early Devonian Posongchong flora of Yunnan: a contribution to an understanding of the evolution and early diversification of vascular plants. Beijing: Science Press. Fig. 6.viii, p. 246. ISBN978-vii-03-036616-0.
20. ^ Taylor, Taylor & Krings (2009), p. 267ff.

External links [edit]

• Lycophytes
• Fossil Groves
• Paleo Plants

burrellfroccattled.blogspot.com

Source: https://en.wikipedia.org/wiki/Lycophyte

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