If you prick us, do we not bleed? if you tickle us, do we not laugh? if you poison us, do we not die? and if you wrong us, shall we not revenge?
This is a quote from Shakespere’s play The Merchant of Venice, Act 3, Scene 1. I’ll apply Shylock’s monologue, a plea against antisemitism, to a potentially prickly and threatening part of a plant, the leaves of a holly arbust. To me and perhaps to others these rather unique leaves are part of the holiday season and hence are charming.
But what brings them about — apart of course for their symbolic and emblematic importance at Christmas time.
The answer is that these leaves serve as the defensive armor of the plants against its predators, namely herbivores. Scientists studying this small tree report that, once a normal-looking leaf or leaves are eaten by herbivores, the plant takes steps to better protect itself. It signals to its DNA through methylation — i.e., by adorning it with methyl groups, with formula CH 3 — which induces leaves to change from a smooth edge to a spiky and prickly
one.
Plants thus defend themselves against herbivores — whether insects or other animals such as mammals — with a wide array of defenses. Probably, the best known if not the most frequent, is secretion of toxic molecules to poison and thus deter their aggressors.
Back to the holly. The name in English, as well as that in French, houx, stems from the Germanic huls for that plant. It features, in addition to these remarkable leaves, lovely looking red berries. Did you know? They are good for the body, not only for the soul! A brandy is prepared, when they are ripe and after maceration. This eau de vie de houx, a specialty from Alsaian vintners, is utterly delicious!
Let us end this piece with another quote, not by Shakespeare but by G. K. Chesterton: “In the round of our rational and mournful year one festival remains out of all those ancient gaieties that once covered the whole earth. Christmas remains to remind us of those ages, whether Pagan or Christian, when the many acted poetry instead of the few writing it. In all the winter in our woods there is no tree in glow but the holly.”