The phylum of seedless vascular plants has about 1000 known living species, including those in the genera Lycopodium and Selaginella; the gametophyte of some of these species cannot photosynthesize, and instead uses mycorrhizae to obtain nutrients.

The Pteridopyhta, phylum of seedless vascular plants has about 1000 known living species, including those in the genera Lycopodium and Selaginella; the gametophyte of some of these species cannot photosynthesize, and instead uses mycorrhizae to obtain nutrients.

Explanation:

The pteridophytes, most advanced group of plant among the cryptogams i.e. seedless plants.

They are first land plants that have developed a well defined vascular  system.

Ferns, horsetails etc are common members of this phylum.

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