Editing Calluna (section)

==Description==
''Calluna'' can reach {{Convert|60|cm}} in height.<ref>{{Cite book |last=Francis-Baker |first=Tiffany |title=Concise Foraging Guide |date=2021 |publisher=[[Bloomsbury Publishing|Bloomsbury]] |isbn=978-1-4729-8474-6 |series=[[The Wildlife Trusts]] |location=London |pages=45}}</ref> It has small-scale [[leaves]] (less than 2–3&nbsp;mm long) borne in opposite and [[decussate]] pairs, whereas those of ''[[Erica (plant)|Erica]]'' are generally larger and in whorls of 3–4, sometimes 5.<ref name=Stace>[[Clive Stace]], (2010) ''New Flora of the British Isles'', 3rd edition. Cambridge University Press.</ref> It flowers from July to September.<ref name=CTW>{{cite book |author=A.R. Clapham |author2=T. G. Tutin |author3=E. F. Warburg |date=1981 |title=Excursion Flora of the British Isles |publisher=Cambridge University Press |edition=3 |isbn=0-521-23290-2}}</ref>{{rp|231}}  In wild plants these are normally [[mauve]], but white-flowered plants also occur occasionally.  They are terminal in [[raceme]]s with sepal-like [[bract]]s at the base with a superior ovary, the fruit a [[capsule (fruit)|capsule]].<ref>Parnell, P. and Curtis, T. 2012. ''Webb's An Irish Flora''. Cork University Press {{ISBN|978-185918-4783}}</ref> Unlike ''Erica'', ''Calluna'' sometimes sports [[double-flowered|double flowers]]. ''Calluna'' is sometimes referred to as Summer (or Autumn) heather to distinguish it from winter or spring flowering species of ''Erica''.{{Citation needed|date=January 2021}}

=== Chemistry ===
[[Phenolic compound]]s in the shoots of ''Calluna vulgaris'' include [[chlorogenic acid]] and a novel phenolic glycoside, most of which are found in greater number during the summer.<ref>{{cite journal |author=Mahbubul, A.F. Jalal |author2=David J. Read |author3=E. Haslam |author3-link=Edwin Haslam |year=1982 |title=Phenolic composition and its seasonal variation in Calluna vulgaris |journal=Phytochemistry |volume=21 |issue=6 |pages=1397–1401 |doi=10.1016/0031-9422(82)80150-7|bibcode=1982PChem..21.1397J }}</ref>

The [[nectar]] of ''Calluna vulgaris'' contains a megastigmane, callunene, that is inhibitory at naturally occurring concentrations to a common [[Trypanosomatida|trypanosome]] parasite of bumble bees, ''[[Crithidia bombi]]''.  Koch et al. elucidate the mechanism of activity that results in the loss of the parasite's flagellum, leading to reduced infectivity, because the flagellum is crucial to anchoring in the insect gut.<ref>{{cite journal |author=Koch, H. |author2=Woodward, J. |author3=Langat, M. |author4=Brown. M.J.F. |author5=Stevenson P.C. |date=2019 |title=Flagellum Removal by a Nectar Metabolite Inhibits Infectivity of a Bumblebee Parasite |journal=Current Biology |volume=29 |issue=20 |pages=3494–3500 |doi=10.1016/j.cub.2019.08.037 |pmid=31607528 |doi-access=free|bibcode=2019CBio...29E3494K }}</ref>