Yes, the Poinsettia. Good answer!
Did you know that the Poinsettia is named after Joel Roberts Poinsett? That's why the plant's name is capitalized, unlike, say, a daisy. As you know, proper nouns begin with a capital letter.
dark chocolate -vs- Swiss chocolate
chardonnay -vs- Champagne
suit coat -vs- Nehru jacket
carnival ride -vs- Ferris wheel
World Wide Web is a proper noun. That's why Web site, i.e. not website, is the correct usage. As is Web page, but not webcam, webcast and webmaster. Go figure.
Back to the holidays. Want to know more about the Poinsettia? Read the article in Carpinteria Magazine, which I wrote. You'll find it on page 84.