Monday, October 08, 2007

Apples on Oaks???

Have you ever heard of oak apples? There are a couple such galls, above, on one of my turbinella scrub oaks. Far more visible than mere acorns. Made by a wasp.

Similar little wasps made this gall, which looks like a yarn plaything for a cat.

For an easier close-up, I broke off the twig and brought it indoors. Upon consulting The Google, I found that nationwide there are some 800 different kinds of oak galls and maybe 100 types in Arizona. One article noted: They are formed entirely from the mutated cells of the tree itself, but the spark of their creation comes from an insect. A tiny wasp, no larger than the exposed tip of a ball point pen, lays its egg in newly forming tissue on the tree. Compounds secreted by the larva when it hatches induce the tree to form the gall, which then provides both protection and food for the developing larva until it emerges as a fully formed adult.

Except, I discovered, that the bridled titmouse, who hangs out with those small generic bird flocks, relishes gall residents!

I don't know if this gall is the same as or different from the pretty pink fluff. The references note that wasps lay their eggs when leaves are just emerging in spring; this photo was taken in October last year and the pink gall in mid-September, if that is any clue.

Here are a couple of well weathered, long abandoned stem galls; among the goodies The Google delivered was the site for an art print of a stem gall! From my searches, I also learned 1) that oak galls were the basis for black ink in the Middle Ages in Europe and for black dye in pre- Columbian America, 2) that they had/have uses in herbal medicine, and 3) that my Sson had coauthored a scientific paper on oak galls published in 1999. For the record, his doctoral thesis dealt with galls on willows. Small world, isn't it?

Linkety Link! I just got off the Florida Turnpike with k, whose long trip home is finally finished. You might want to get in the right hand seat & ride with her. Quite a lady! But what I didn't know was that the giant kudzu vine that ate the South had reached the Sunshine State.


Jan said...

Your posts are always wonderful.

I learn new things all the time!

OmegaMom said...

That pink feather-duster is just too cool.

Granny J said...

Hi, Jan -- I learn new things all the time, too. Frinstance, that all these galls don't appear to hurt the oaks. And that some galls are merely folded leaves.

Dotter -- Agree. I'm still puzzled whether the orange fuzz is merely tired pink fuzz. And I really should have harvested and cut open one of those apples to show the insides!

Lucy said...

Aren't they fascinating - I've long been intrigued by them, but haven't been able to get such good picturesa as these. Mind you, ours aren't as impressive as the pink fluffy one. I'm not sure about cutting one open, seems a bit unkindly intrusive on the critter within!

meggie said...

Always something wonderful to discover here!

smilnsigh said...

These galls are all the same, yet different? All made by a wasp? But the top ones really resemble apples.

Never heard of such!!!!!! Thank you.


Granny J said...

Lucy -- I have seen the interior (my Sson is Dr. Science, after all) and it is fibrous, with a little nest at the center. But, like you, I'm a bit tender-hearted.

Meggie -- the whole world and every little piece of it is a wonderful place for exploring!

SnS -- unlike apples, the center is only fit for a titmouse.

omegadad said...

Great Galls of Fire, Mom. (I liked the clouds too... none of our nimbos have cumuli.)

Granny J said...

Welcome, OD -- you certainly aren't one to let an opportunity for a good pun to pass by, are you. BTW, those particular clouds were not only choice, but rather rare for this time of year.

School for Us said...

Thanks for leaving a comment on my blog about my galls. I guess this is a popular topic this time of year. :-) I'm off on a gall hunt tomorrow, and hoping to find something exciting like your pink gall!

teacher of one said...

School for Us sent me your way.
I posted what must have been one of these galls earlier this summer and have been trying to ID it. I linked to your post in my update. Please check out my possible gall it is very different.

Granny J said...

school -- happy hunting. If you got oaks, you got galls!

teach -- I'm on my way to take a look, not that I'm any sort of gall expert; I merely take pictures of things that I find interesting. BTW, a lot of galls look like folded-over leaves.

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