Bryophyte pesticides. The liverwort, "Plagiochila," produces a chemical that is poisonous to mice. Other bryophytes produce chemicals that are antifeedants which protect them from being eaten by slugs. When "Phythium sphagnum" is sprinkled on the soil of germinating seeds, it inhibits growth of "damping off fungus" which would otherwise kill young seedlings. Commercial Peat is a fuel that is produced from dried bryophytes, typically "sphagnum." Bryophytes antibiotic properties and ability to retain water make them a useful packaging material for vegetables, flowers, and bulbs. Also, because of the antibiotic properties, "sphagnum" was used as a surgical dressing in World War I.
Portlethen Moss have been enhanced by proximity to the sea and natural defensive protection of the moss to impede intruders. From Tacitus accounts of the Roman general Agricola, it is known that the Romans were daunted by Portlethen Moss, Netherley Red Moss, Cookney Moss and other local bogs that hindered travel. This is also evidenced by the Roman Camp of Raedykes having been established immediately south of this cluster of mosses; the Romans not being able to progress further north, turned inland toward Netherley.The Portlethen Moss is near the Grampian Mountains. The ancient Causey Mounth passage specifically connected the Bridge of Dee