def porttree_matches(name):
    '''
    Returns a list containing the matches for a given package name from the
    portage tree. Note that the specific version of the package will not be
    provided for packages that have several versions in the portage tree, but
    rather the name of the package (i.e. "dev-python/paramiko").
    '''
    matches = []
    for category in _porttree().dbapi.categories:
        if _porttree().dbapi.cp_list(category + "/" + name):
            matches.append(category + "/" + name)
    return matches