Complex sentence: They returned in 1918, Smith bringing 600 species of plants, where off about 50 were new to science, the best known species being the "Pinus canariensis", the Canari Island pine.
Split into simpler sentences: They returned in 1918, Smith bringing 600 species of plants, where off about 50 were new to science. The best known of Smiths new species is probably the "Pinus canariensis", the Canari Island pine.