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Nectary: noun, biology; ‘a nectar-secreting glandular organ in a flower (floral) or on a leaf or stem (extrafloral)’ (Oxford Dictionary).

230503 extrafloral nectaries (1)

Like most people, I knew that most flowers produce nectar as a reward to attract pollinators but I’ve only recently learned that many plants produce nectar through extrafloral nectaries, as the definition explains, on their leaves or stems. I read that these particular nectaries can be found on many species of fern, and I’ve finally found some examples on the stems of Bracken (Pteridium aquilinum) that has just begun to sprout locally. The nectaries are the small smooth pale lumps on the back of the stipe, and, in Bracken, their purpose is apparently to attract ants that will then defend the fern against the insects that might eat it, like some species of bug and fly, and the larvae of various moths, amongst others.

230503 bracken and ant

ant leaving nectary on Bracken

However, I also found a journal article, referenced below, which reported that the ants actually had ‘no significant effect on bracken-specific herbivores’ so, in this case, the plant may be producing nectar for nothing.

Reference: ‘Bracken, Ants and Extrafloral Nectaries. I. the Components of the System’, J. H. Lawton and P. A. Heads, Journal of Animal Ecology, vol. 53, no. 3, October 1984, pp. 995-1014. I do not have access to Jstor so was only able to read the information contained in the article summary.

230503 common froghopper nymphs

Common froghopper nymphs on Bracken