Is there a tree-ologist in the audience?

20Dec06

It turns out that there aren’t too many students around Cambridge during the Christmas break*. My curiosity has correspondingly shifted towards the flora rather than the fauna of the area, and I’ve recently been fascinated by a type of tree that is common on the western part of the city.

*-by the way, it really is the Christmas break, not the “Winter Holiday Break” as “politically correct” Americans might be quick to interject. This isn’t a matter of not being sensitive to other cultures (particularly the South Asian population), but rather that British culture is much more secularized and ‘Christmas’ is used de-facto as a ‘generic winter holiday.’

Anyway, after the most of leaves fell, I noticed the following strange sight:

There were little round balls of leaves in these trees that didn’t die and fall off. One might be quick to pass them off as bird nests, but closer inspection will verify that they’re not.  Here’s a closer look from outside of Churchill college:

Finally, here’s an even closer photo of one of the ‘leaf balls.’ The trees have little red buds while the ‘leaf balls’ have white buds.

I’ve been having trouble identifying this particular tree species and consequently have been unable to read up on it. (It may be a strawberry tree, Arbutus unedo.) However, it has really piqued my curiosity (though nobody else’s) for a few reasons:

  1. Why didn’t these leaf balls fall off and die like the rest of the leaves on the tree? What purpose does this serve? Why would this tree only be mostly-deciduous, but not completely so?
  2. How would a given ball of leaves differentiate itself and tell itself, “hey guys, this winter let’s do something crazy and stay on the tree!” Is there some kind of trigger? Since the buds are different colors, might this have to do with pollination? How and why do these bunches of leaves stay in a spherical shape?
  3. What is the significance of the colors of the flower buds?

Anyway, if anyone has any insight on these trees, I’d be very interested to hear it. The leaf balls are like wonderful, natural Christmas ornaments.



3 Responses to “Is there a tree-ologist in the audience?”

  1. 1 robert

    What you have come across is mistletoe – a parasitic plant that hitches a ride on other trees. So its leaf-shedding etc. is entirely independent of the host plant. Mistletoe is indeed pressed into service as a traditional Christmas decoration, its white berries having symbolic overtones much like the red berries on holly. At a more pagan and non-new man level, it can used by those desperate to make a move with the opposite sex: one whips out out a sprig of mistletoe ands claims a kiss. This sort of thing might well be frowned upon these days. Whatever – have a Merry Christmas and a Happy New Year.

  2. Wow! Real mistletoe! They *are* Christmas ornaments! I suspected there might be something mysterious going on in terms of a different plant species, but wasn’t sure if I was being too fanciful. That’s very exciting! Thanks Robert!

  3. Don’t ever be tempted to pick or cut mistletoe from the tree — it’s frightfully bad luck unless it’s full moon and you’re a fully paid-up druidic sky clad virgin. Much better to buy a sprig and let someone else have the bad luck.



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