Prunella – mistress of plasticity

Now that I have your attention, this is not an article about soft porn or fetishes, but rather a paean for that humble ‘weed’ Prunella vulgaris – Self-heal, Heal all, Woundwort, Heart of the Earth and many other names, depending on where in the World you come from.   Prunella vulgaris is in the family Lamiaceae, so related to mints and dead-nettles.  It is an edible weed, the young leaves can be used in salads and it can also be used in soups, stews, or used whole and boiled as a pot herb.

The instantly (to me at any rate) recognisable flower of Prunella vulgaris

Prunella as I will now familiarly call her, has a very wide geographical native range and has also been introduced into South America where she does very well indeed (Godoy et al., 2011).

Distribution of Prunella vulgaris, blue native, brown introduced. http://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:455176-1

 The name Prunella is derived from ‘Brunella’, a word which is itself a derivative, coming from the German name for quinsy, (a type of throat inflammation), die Braüne, which it was historically used to cure.  That is the other aspect of this glorious plant, it has many medicinal properties, hence the many common names refer to its healing powers, almost as many as Athelas of Lord of the Rings fame 😊  It was traditionally used in European herbal medicine for sore throats, fever reduction and like Athelas, for accelerating the healing of wounds (Matthiolus, 1626).  More recently it has become of interest as a possible cure for conditions associated with the herpes simplex virus (Psotováa et al., 2003) and inhibiting anaphylactic shock and other immediate type allergic reactions (Shin et al., 2001).  So truly a wonder drug, and again proving that “Old Wives Tales” are in many cases based on more than just superstition.

My interest in Prunella vulgaris, is however, based on its wondrous plasticity, as the three photographs below show nicely.  Depending on grazing (or mowing) pressure, Prunella can grow to reproductive maturity at heights  ranging from just over 2 cm to just under 30 cm. Truly remarkable.

I am of course, not the first person to be fascinated by this plasticity and the taxonomic and evolutionary ins and outs of this lovely plant (Nelson, 1965; Warwick & Briggs, 1979) but I still find it fascinating, and who knows, perhaps one day I might do some work on it myself 😊

The other thing that I like about Prunella is that she is also provides a living for aphids.  She has her own rare and specific one, Aphis brunellae, but is also kind enough to let a few other species make a living on her, Aphis gossypii, Aphis nasturtii, Aulacorthum solani,  Macrosiphum euphorbiae, the ubiquitous Myzus persicae, M. ornatus and Ovatomyzus chamaedrys (Blackman & Eastop, 2006).

Aphis brunellae, rare in the UK – with thanks to the two Bobs for permission to use the photograph. http://influentialpoints.com/Images/Aphis_brunellae_colony_on_Prunella_vulgaris_c2015-08-21_15-37-27ew.jpg

 

Finally, you will have noticed that the Prunella aphid is A. brunellae, which is derived from the original name of Prunella (I guess Prunella Scales is happy, she could have been Brunella Scales).  Interestingly, her alter-ego was not removed until fairly recently, her tombstone is shown below.

References

Blackman, R.L. & Eastop, V.F. (2006) Aphids on the World’s Herbaceous Plants and Shrubs Volume 1 Host Lists and Keys.  Wiley, Oxford.

Godoy, O., Saldaña, A., Fuentes, N., Valladares, F. & Gianoli, E. (2011)  Forests are not immune to plant invasions: phenotypic plasticity and local adaptation allow Prunella vulgaris to colonize a temperate evergreen rainforest. Biological Invasions, 13, 1615-1625.

Matthiolus, P.A. (1626) Kräuterbuch.  Noringberg.

Nelson, A.P. (1965) Taxonomic and evolutionary implications of lawn races in Prunella vulgaris (Labiatae). Brittonia, 17, 160-174.

Psotová, J., Kolá, M., Sousek, J., Ívagera, Z., Vicar, J. &Ulrichová, J. (2003) Biological activities of Prunella vulgaris extract. Phytotherapy Research, 17, 1082-1087.

Shin, T.Y., Kim, Y.K. & Kim, H.M. (2001) inhibition of immediate-type allergic reactions by Prunella vulgaris in a murine model.  Immunopharmacology & Immunotoxicology, 23, 423–435.

Warwick, S.I. & Briggs, D. (1979) The genecology of lawn weeds III. Cultivation experiments with Achillea millefolium L., Bellis perennis L., Plantago lanceolata L., Plantago major L. and Prunella vulgaris L. collected from lawns and contrasting grassland habitats.  New Phytologist, 83, 509-536.