com /]ONE LOOK DICTIONARY SEARCH[/url], you'll see that almost all dictionaries capitalize Swiss chard , while about half of them capitalize Brussels sprout . Both are obviously proper names and deserving of a capital S and B , respectively. I suggest that the reason for the anomaly may be that the sprout entered the language about 300 years before the chard-- time enough for it to become a common noun among the hoi polloi.
New words, one handy idiom, and a 2-minute quiz — delivered to your inbox to keep your streak alive.