11. "Azolla " are weeds in many parts of the world, entirely covering some bodies of water. 12. Compared to current carbon dioxide levels, these azolla grew rapidly in the enhanced carbon dioxide levels found in the early Eocene. 13. An abundance of phosphorus, due for example to eutrophication or chemical runoff, often leads to " Azolla " blooms. 14. At the time this paper was published, four species of " Azolla " had been described from the fossil record. 15. The sunlight-blocking azolla groves have created " dead zones " in habitats for small fish and other aquatic plant life. 16. "Azolla filiculoidess " ( Red Azolla ) is the only member of this genus and of the family Azollaceae in Tasmania. 17. "Azolla filiculoidess " ( Red Azolla ) is the only member of this genus and of the family Azollaceae in Tasmania. 18. Recent sources include both " Azolla " and " Salvinia " in Salviniaceae, although each genus was formerly given its own family. 19. It is present in New Zealand as an introduced species and an invasive weed that has crowded out a native relative, " Azolla rubra ". 20. Like all ferns, sexual reproduction leads to spore formation, but " Azolla " sets itself apart from other members of its group by producing two kinds.
