OK Botanists - what is it

[SCL]

<p>I'm in the Chicago area...out walking last week along the RR tracks and saw the following growth on leaves....does anybody know what it is...I saw it last year on a some leaves down by a creek and thought it was an infection, but not this time. Details - Canon T90, Walgreens whatever is on sale 200 film, Kiron 105/2.8 lens at f5.6. Handheld. 100% crop. Thanks in advance.</p><div></div>

[Jeff Lear]

<p>If you don't get a response here, I would try a Camellia expert. It appears to be some sort of viral or fungal growth. Something parasitic, for sure.</p>

[chelsea]

<p>I think that is some kind of parasitic worm that causes that kind of growth, some kind of leaf gall. An insect lays an egg on the leaf, and the larvae have some kind of chemical that causes the growth. There's all kind of leaf galls in various forms, oak leaf galls are about one inch balls, some show up as a 1/2 inch circular discolouration, others grow into these misshapen forms.</p>

[chelsea]

<p>Just browsed through my big insect book, there are wasps, aphids and midges that can cause galls. Take a sharp knife and slice one open, you may find the critter inside.</p>

[SCL]

<p>Thanks for the info so far. These are really small delicate little things (they just look big in the photo) about 1/2 the size of a pinhead, so with my clumsy hands, I'd need a microtome to slice one open. I did see another plant with what appeared to be some sort of small gal which looked like small worm feces scattered in discrete piles over the surface of several leaves...but it in no way resembles what is shown in my original picture.</p>

[jwallphoto]

<p>Yeah, you need an entomologist, not a botanist. I've been tempted to buy <a href="http://www.amazon.com/California-Western-States-Natural-History/dp/0520248864">this book</a>, but I don't really run into interesting galls that often. Haven't developed the eye for 'em, I guess.</p>

[photojen]

<p>We have something similar looking to this on our maple trees called maple bladder gall and agree with Rose-Marie.</p>