Privet leaves

[Waterbuffalo]

In a science lesson we were looking at a nail varnish cast of the bottom of a privet leaf. We could clearly see the stomata and guard cells but found some other similar sized structures that looked like barancles? Does any one have any idea what they are??

[theprof]

I can't be certain about this because of insufficient information. For example were you looking at a photomicrograph of the cast, a magnified projected image or at a slide on a microscope stage? Were the barnacles just as translucent as the stomata and guard cells or was any colouration to be seen? Was phase contrast microscopy used?

It's possible that what you've seen are the pustules of some of the many fungal rust species that infect privet such as Phyllosticta or Cercospora species.

There are also creatures called privet mites or ********** which are related to spider mites and are virtually invisible to the naked eye. These can cause damage to the underside of the leaf as you describe. However, in this case, privet mites are only found in the warmer countries of the world, California, Florida and parts of Australia. If the cast was from temperate climes, this is unlikely to be the answer.

Plant galls come in a myriad of different shapes and sizes, but I doubt you've been looking at these as with few exceptions, they are not microscopic in size. Besides, they generally only occur on woody stems and twigs rather than leaves.

Rust is probably the best bet. I assume your teacher didn't know the answer either?

[theprof]

I suppose I'll never know why AB considers "Eri0***** Mites" an obscenity but there you go.

[theprof]

OK last try: read the following word backwards and just add "Mites". diyhpoire.

[gen2]

OK prof, the reason your mite was considered too rude for AB was because the last three letters spell a racial term for a Jewish person.

So now you know.

[theprof]

Yes, I can see it now gen2.

I was taking a break at the annual Christmas bash of the Dstl laboratory where I work as an advisor part-time when I did that post last night. It didn't help that my PA kept making sure my wineglass was always full.

Thanks