Its the stems that give it away. MJ that height would be much bushier and have many more branches/budsites from what I understand but I'm no expert.

Found this pic of Charlottes Web, just didn't find any huge plants to really compare but I think its easy to tell.

http://cbsnews2.cbsistatic.com/hub/i/2014/02/...tesweb.jpg

(hope the pic shows)