Mustard Seeds - Misome - Hybrid. Non-GMO. Brassica campestris Narinosa group. Alt names: Japan green, komatsuna, tasai, tatsoi. 30 days. Warm season annual. A fairly recent hybrid between Komatsuna and Tatsoi, this versatile, uniform, and hardy green grows upright. The 10" tall plant produces tender, thick, savoyed, deep green leaves that hold well in the field. Approximately 15,813 seeds/ounce.