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Which lower vascular plants produce microspores and megaspores?
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Plant reproductive system
A large bumblebee (Bombus species) pollinating a teasel flower head (Dipsacus species).
In the context of lower vascular plants (pteridophytes), most species are homosporous, meaning they produce only one type of spore. However, a few specific groups are heterosporous, producing two distinct types of spores: larger megaspores and smaller microspores.123
The lower vascular plants that exhibit this heterosporous condition include:
- Lycophytes: The genera Selaginella (spike mosses) and Isoetes (quillworts) are both heterosporous.45
- Ferns: Certain water-fern families, specifically Marsileaceae, Salviniaceae, and Azollaceae, are heterosporous.1
In these plants, megaspores develop into female gametophytes, while microspores develop into male gametophytes. These spores are produced in specialized structures called megasporangia and microsporangia, which are often associated with modified leaves known as megasporophylls and microsporophylls, respectively.43