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The Lycopodiopsida are a class of plants often loosely grouped as the fern allies. Traditionally, the group included not only the clubmosses and firmosses, but also the spikemosses (''Selaginella'' and relatives) and the quillworts (''Isoetes'' and relatives). However, the latter are now usually placed into a separate class, Isoetopsida. Clubmosses are thought to be structurally similar to the earliest vascular plants, with small, scale-like leaves, homosporous spores borne in sporangia at the bases of the leaves, branching stems (usually dichotomous), and generally simple form. The class Lycopodiopsida as interpreted here contains a single living order, the Lycopodiales, and a single extinct order, the Drepanophycales. ==Order Lycopodiales== The classification of this group has been unsettled in recent years and a consensus has yet to emerge. Older classifications took a very broad definition of the genus ''Lycopodium'' that included virtually all the species of Lycopodiales. The trend in recent years has been to define ''Lycopodium'' more narrowly and to classify the other species into several genera, an arrangement that has been supported by both morphological and molecular data and adopted in numerous revisions and flora treatments. Starting from the four genera accepted by Øllgaard,〔, cited in 〕 a study based on chloroplast DNA produced the cladogram shown below (reproduced here to genus level only), confirming the monophyly of the four genera, and their distance from ''Isoetes''. | 2=''Isoetes'' }} }} The genera fall into two distinct clades, but there is, as yet, no consensus as to whether to recognize them in a single family, Lycopodiaceae, or to separate them into two families: a more narrowly defined Lycopodiaceae and Huperziaceae. The family Lycopodiaceae, as narrowly defined, comprises the extant genus, ''Lycopodium'', which includes the wolf's-foot clubmoss, ''Lycopodium clavatum'', ground-pine, ''Lycopodium obscurum'', southern ground-cedar, ''Lycopodium digitatum'', and other species. Also included are species of ''Lycopodiella'', such as the bog clubmoss, ''Lycopodiella inundata''. Most of the ''Lycopodium'' species favor acidic, sandy, upland sites, whereas most of the ''Lycopodiella'' favor acidic, boggy sites. The other major group, the family Huperziaceae, are known as the firmosses. This group includes the genus ''Huperzia'', such as the shining firmoss, ''Huperzia lucidula'', the rock firmoss, ''Huperzia porophila'', and the northern firmoss, ''Huperzia selago''. This group also includes the odd, tuberous Australasian plant ''Phylloglossum'', which was, until recently, thought to be only remotely related to the clubmosses. However, as the cladogram above shows, it is closely related to the genus ''Huperzia''. Lycopodium powder, the dried spores of the common clubmoss, was used in Victorian theater to produce flame-effects. A blown cloud of spores burned rapidly and brightly, but with little heat. It was considered safe by the standards of the time. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Lycopodiopsida」の詳細全文を読む スポンサード リンク
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