Hi, I have never seen this kind of weird looking plant. It looks like a parasitic plant that attached on the back of the leaf. The origin is from mountain side of Southern Taiwan and I don't have additional photo. Please let me know if you have an answer. Thank you.
They do look like flowers, maybe the tree is one that flowers off the leaves - this behavior is not entirely unknown.
Possibly a really remarkable gall. Doesn't look anything like a Tilia bract/inflorescence or a Davidia. I'd check with a gall expert. An expert on the China/Taiwan flora might also be helpful. Regrettably, my Taiwan experience is confined to Taipei.
One more piece of information: I have a very good guess of what the "hosting" tree is. I think this tree does not normally produce flower from its leaf.
If those are flowers then that might be a modified stem such as a cladode or phylloclade. You might find something by using those search words.
"Four cecidomyiid galls on Machilus zuihoensis Hayata in the Guandaushi forest have been recorded (Yang et al., 1996). They are urn-shaped, mouse-shaped, coniform, and spindle-shaped galls." http://ejournal.sinica.edu.tw/bbas/content/1999/2/bot402-08.html
They look too structured to be a gall, but you might send a photo to these people to see what they think. http://www.plantengallen.com/engels.htm
After a lot of googleing I am convinced that it is one kind of remarkable insect galls. Thank you all for your contribution.
If you can figure out just what it is--let us know. I was briefly wondering if it could be some really weird parasitic plant that behaves like some of the dwarf mistletoes or Rafflesiaceae. If it's a gall, it's amazing.
Galls can be amazing. Look at this thread: http://www.botanicalgarden.ubc.ca/forums/showthread.php?t=4260&highlight=woses
I just come across this link a minute ago. http://subject.forest.gov.tw/species/gall/html/mmenu.htm More photos of its kind. It is in Chinese language but you can still read some of the scientific name. Click the sub-link on the left, you can see more photos of various different exotic insect galls.
Dave-Florida, It was you who first pointed it to the right direction and suggested insect galls. Nice job! Thank you!
Is the tree they are growing on some sort of Eucalypt??? They sometimes get galls on them but can't say they look like these. Liz
The gals are probably on Machilus zuihoensis or one of the other species of Machilus, which is very similar to Persea (the avocado genus). Family Lauraceae.
