Megaspores are present in heterosporousplants. These types of plants have two spore types, megaspores and microspores. Generally speaking, the megaspore, or large spore germinates into a female (egg-producing) gametophyte, which is fertilized by the microspore. Plants which are known to do this include those in the following genera: Heterosporous plants, such as spikemosses, quillworts, and some aquatic ferns produce spores of two different sizes: the larger spore effectively functioning as a female spore and the smaller functionally male. ... For other uses, see Plant (disambiguation). ... Spores produced in a sporic life cycle. ...
Selaginella: the spikemosses, included within the lycopod, or clubmoss group
Selaginella A member of phylum Lycophyta, adapted for dry conditions (xerophyte). ... Marsileaceae Categories: Stub | Plant families | Pteridophyta ... Marsilea is a genus of approximately 65 species of aquatic ferns of family Marsileaceae. ... Species Azolla caroliniana Willd. ... Species Azolla caroliniana Willd. ... This article is about the group of pteridophyte plants. ... Genera Salvinia The Salviniaceae are a family of ferns, which contains the single genus Salvinia. ... Genera Salvinia The Salviniaceae are a family of ferns, which contains the single genus Salvinia. ... This article is about the group of pteridophyte plants. ...
The rest of Mirbelieae have two kinds of very distinct megagametophytes, the newly described Mirbelia- and Jacksonia-types.
They differ collectively from the Polygonum type in being derived from other than just the megaspore located at the chalazal end, having other than the uniform 8 nuclei per megagametophyte, and in numbering often more than 1 per ovule.
It is suggested that part of the driving force behind megagametophyte variation seen in these tribes is apomixis.
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