A great resource by Eric Meier, generously shared at The Wood Data-Base.
Here you will find a well organized collection of wood species with good colour photos of unfinished, finished, end grain and others photos of the especimens.
A great description that will take you true the common and scientific names, specific gravity, shrinkage and more, into a detailed description of colour, appearance, grain, texture… to the prices,sustainability, uses, prices…
All this information is categorized in a format that is really easy to read and understand, making it possible to go directly to the information needed. Is writen directly to the point, no extra fluff.
You will find also good amount wood related articles that are informative, concise and helpful.