Linked from
The 27 pages that link to Seed plant, each with the reason it gives.
GymnospermNarrower topic: Gymnosperms are one of the two major living branches of seed plants.
PollenNarrower topic: Pollen is the male reproductive dispersal stage shared by seed plants.
Seed coneNarrower topic: Seed cones are one reproductive innovation within seed plants.
BennettitalesNarrower topic: Bennettitales belong to this broad group of vascular plants.
GnetidaeNarrower topic: This broader lineage includes both gymnosperms and flowering plants.