Note 11 — Chapter I
Reading edition
Ferns constitute one sixth of the flora of South America; Spruce counted 140 species within the space of three square miles. Their limits of growth are 500 and 7000 feet above the sea.
Reading edition
Ferns constitute one sixth of the flora of South America; Spruce counted 140 species within the space of three square miles. Their limits of growth are 500 and 7000 feet above the sea.