The flare activity of C stars as a function of the temperature. This figure comprises stars whose rotation periods are shorter than the corresponding period of the 30 Myr ischrone of the I sequence. The temperature range is 3000 < T_eff < 6400. Most of those stars are C stars, although a small part of them may be I stars that are younger than 30 Myr. The green dashed line is a polynomial fitting and the red dashed line is a Gaussian fitting.