※ This (titular) assertion is questionable, so I'm (1) putting it in quotes, and (2) placing an asterisk in front of it.
The following page starts with this assertion, which I had not heard before :
The Japanese language does not have words that function as adjectives in a syntactic sense – that is to say that tree diagrams of Japanese sentences can be constructed without employing adjective phrases. 
Nevertheless, there are words that function as adjectives in a semantic sense.
 ! ! !
Is this a commonly heard notion?
For example :
It's not obvious how Parse Trees of these strings (above) would be any different from Parse Trees of English strings of similar meanings.
–- that is to say, a tree diagram (or a parse tree) of the latter Japanese string (the sentence) seems like it would be a great example to illustrate [adjective phrases] in Japanese.
This Jp wikipedia page doesn't have anything on it: Wikipedia 形容詞