Vascular plants, also referred to as higher plants (Tracheophyta), can be roughly divided into four main categories: clubmosses (Lycophyta), ferns, gymnosperms and flowering plants. Clubmosses and ferns reproduce via spores (cryptograms), while gymnosperms and flowering plants are seed plants (spermatophytes).
Around 490 vascular plants grow wild in Iceland (see list of wild flowering plants and ferns in Iceland), a figure that includes both native plants and imported plants that have colonised the island. Over 300 of these plants are dicotyledons (dicots). Of the remaining species, around 150 are monocotyledons (monocots). The simplified classification system defined by Bergþór Jóhannsson in 2004 puts the number of hawkweed (Hieracium spp.) species in Iceland at 22. Around 31 fern species and 9 species of clubmoss grow in Iceland. Only four gymnosperms are found in Iceland, three of which are recent arrivals: the Siberian larch, lodgepole pine and Sitka spruce. The juniper is the only gymnosperm native to Iceland.