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Plants that are homosporous produce spores of the same size and type. Heterosporous plants, such as seed plants , spikemosses , quillworts , and ferns of the order Salviniales produce spores of two different sizes: the larger spore (megaspore) in effect functioning as a "female" spore and the smaller (microspore) functioning as a "male".
Drepanophycales is an order of extinct lycophyte plants of Late Silurian to Late ... Homosporous, with sporangia borne singly and dehiscing by a single slit. List of ...
The following phylogram shows a likely relationship between the other vascular plant classes and the leptosporangiate ferns. It was formerly unclear about the relationship between Equisetopsida , Psilotopsida , and Marattiopsida , [ 14 ] [ 15 ] [ 16 ] but recent studies have shown that Equisetopsida is most likely sister to Psilotopsida.
All vascular plants are sporophyte dominant, and a trend toward smaller and more sporophyte-dependent female gametophytes is evident as land plants evolved reproduction by seeds. [7] Those vascular plants, such as clubmosses and many ferns, that produce only one type of spore are said to be homosporous.
Most non-vascular plants, as well as many lycophytes and most ferns, are homosporous (only one kind of spore is produced). Some lycophytes, such as the Selaginellaceae and Isoetaceae , [ 7 ] : 7 the extinct Lepidodendrales , [ 8 ] and ferns, such as the Marsileaceae and Salviniaceae are heterosporous (two kinds of spores are produced).
Some lycophytes are homosporous while others are heterosporous. [5] 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.
The use of C. richardii in genetic research studies has been valuable to understanding fern and plant evolution as a whole, and in 2019 "C-fern" became the first homosporous fern to have its genome partially assembled, thus acting as a reference genome to which other ferns can be compared. [9]
Equisetum (/ ˌ ɛ k w ɪ ˈ s iː t əm /; horsetail) is the only living genus in Equisetaceae, a family of vascular plants that reproduce by spores rather than seeds. [2]Equisetum is a "living fossil", the only living genus of the entire subclass Equisetidae, which for over 100 million years was much more diverse and dominated the understorey of late Paleozoic forests.