Wednesday, 22 May 2013

Wednesday Wildflower: Brazilian pepper tree

I've been wondering about some trees in Sunnynook Park every time I visit Auckland.  From the shape of their leaves and their panicles of small flowers I had assumed they're something in the Cunoniaceae. But I should have been more curious and looked more closely, because these leaves are alternate, whereas Cunoniaceae have opposite leaves with interpetiolar stipules.

Schinus terebinthifolius, a flowering branchlet from a female tree.
This week I was there again and saw one of the trees had little round pinkish fruits, and I realised this is Schinus terebinthifolius.  I knew S. molle, which has more graceful hanging leaves, and I knew the fruits of S. terebinthifolius are the pink peppercorns you sometimes see mixed with black peppercorns (Piper nigrum) in pepper grinders. (Pink pepper, confusingly, is made with true black peppercorns, using newly-ripened berries and treating them with brine and vinegar, described by McGee, 2004.)


It's becoming a bit of a problem weed in New Zealand and worrying some weed experts.  Back in 1988, Flora of New Zealand Vol. 4 didn't record it as naturalised (Webb et al. 1988), but now it seems to be establishing.  It's a major weed in many warmer countries.  The trees in Sunnynook Park don't seem to be spreading, although there appear to be suckers coming up from the roots.  Most of the trees there are male, but I did spot a couple of females.

It seems a lot of our new weeds are woody, and many are bird-dispersed.  I wonder how many originate from more tropical climates and owe their success here to climate change.

The Flora says it has 5–9 leaflets.  The leaf I randomly chose to photograph had 11:
Schinus terebinthifolius leaf
That doesn't mean the identification is wrong.  Many characteristics of plants are more variable than the descriptions cover, partly because the descriptions are based on a smallish sample that doesn't allow for the odd extreme.

Pink pepper is in the family Anacardiaceae, the same family as mango, cashew, and poison ivy; some people are very allergic to this family.  According to McGee (2004) it owes its peppery flavour to cardanol, an irritating phenolic compound.

References.

McGee, H. 2004.  On food and cooking, the science and lore of the kitchen. (Revised edition), Scribner.

Webb, C.J.; Sykes, W.R.; Garnock-Jones, P.J. 1988.  Flora of New Zealand Vol. 4.  Botany Division, DSIR.

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