Komatsuna!

Wondering what those leaves are in your box this week--the ones that aren't spinach, or kale, or lettuce, or beet greens, or cilantro?  Turns out they're komatsuna, or Japanese mustard spinach, aka  Brassica rapa.  Use them like spinach, or any other green.  Here's a good-sounding recipe that specifies komatsuna.