Crocus or crocuses

What is the plural for a Crocus. is it Crocuses, Croci or is it singular and plural in one word. I could do an Internet search but I'm not interested enough in the answer to be bothered to do so.
Anyway or everyway it may be. Here are two Crocus flowers from the same bulb. Does that make them plural? Maybe they are just one plant called a singular Crocus? Oh what the heck, I'll photograph Sheep from now on, that's easier.