Give up Myriam?
I have mostly only search for the genus name and not each species, and it is easier using the highlighting method,with a right click you can instantly do a google search then go to images. Sometimes searching for a species will bring different results, and often a site which gives more clues even if the correct plant hasn't come up. Also by looking at more images than on the first image search page brings results, or looking at a link on the web search where I sometimes find things which don't come up in an image search.
I have found more photos of Zornia species, some do have the same growth habit but as in many genera they can vary hugely even in flower type so the best thing you can go on is leaf type and habit, seed pods are a good incication too.
http://hvsh.cria.org.br/hv?act...
An example of how to find photos not on an image search, this site in a web result has a link at the bottom to Missouri Botanical Garden..
http://www.tropicos.org/Name/1...
Going to the site, I search for Zornia and get a list of links..
http://www.google.com/cse?cx=0...
Clicking on the second link I get a list of links to photos.. none of the Zornia sp. there match, but it shows how they can be found when not in an image search. I found more photos somewhere else but I don't recall where I found them, one species showed a similar growth habit but the leaves were different.
http://www.mobot.org/mobot/mad...
