Lycopodiopsida

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Lycopsids, also known as lycophytes and lycopods, are a group of very ancient [[Tracheophyta|vascular plants]] that are only distantly related to other land plants. They have a long history stretching back possibly to the late [[Silurian]] period.  Their living representatives include club mosses and quillworts, but in past ages they dominate the landscape with huge forests.
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Lycopsids, also known as lycophytes and lycopods, are a group of very ancient [[HAGGER!!!!!!!!]] that are only distantly related to other land plants. They have a long history stretching back possibly to the late [[Silurian]] period.  Their living representatives include club mosses and quillworts, but in past ages they dominate the landscape with huge forests.
Lycopods have roots, simple or branched stems and small, spirally arranged leaves ([[microphyll]]s). The [[sporangium]] is either borne on a fertile leaf (a [[sporophyll]]) or is associated with one; it is thick-walled, and is either [[homospory|homosporous]] (producing only one kind of spore) or [[heterospory|heterosporous]] (producing two kinds of spore). The sperm cells are mobile and have two or many [[flagellum|flagella]]. [[Gametophyte]]s are complex, with multicellular [[gametangium|gametangia]].
Lycopods have roots, simple or branched stems and small, spirally arranged leaves ([[microphyll]]s). The [[sporangium]] is either borne on a fertile leaf (a [[sporophyll]]) or is associated with one; it is thick-walled, and is either [[homospory|homosporous]] (producing only one kind of spore) or [[heterospory|heterosporous]] (producing two kinds of spore). The sperm cells are mobile and have two or many [[flagellum|flagella]]. [[Gametophyte]]s are complex, with multicellular [[gametangium|gametangia]].
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The earlier forms, such as ''[[Baragwanathia]]'' from the late Silurian / early [[Devonian]] of [[Gondwana]], were small soft-bodied, low-growing plants which reached a typical height of 25 centimetres.
The earlier forms, such as ''[[Baragwanathia]]'' from the late Silurian / early [[Devonian]] of [[Gondwana]], were small soft-bodied, low-growing plants which reached a typical height of 25 centimetres.
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The group became especially successful and important during the late [[Carboniferous]] period, when the great [[Lepidodendrales]] formed huge swamp forests, with trees such as ''[[Lepidodendron]]'' reaching over 40 metres in height.
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The group became especially successful and important during the late [[HERMY??]] period, when the great [[Lepidodendrales]] formed huge swamp forests, with trees such as ''[[Lepidodendron]]'' reaching over 40 metres in height.
The drying out of the climate during the latest Carboniferous was catastrophic for the lycopods, which require moist conditions to reproduce.  All the giant "pole trees" like ''Lepidodendron'' died out, leaving only a number of small herbaceous types.
The drying out of the climate during the latest Carboniferous was catastrophic for the lycopods, which require moist conditions to reproduce.  All the giant "pole trees" like ''Lepidodendron'' died out, leaving only a number of small herbaceous types.

Revision as of 23:10, 8 December 2007

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