Jiaxing is known as the "granary in northern Zhejiang", and rice is the most important food crop in Jiaxing. As shown in the picture, it is a rice plant. The following is a description of rice.

A, the stems of rice belonging to herbaceous plants cannot be thickened continuously, so it is wrong;

B, the roots of rice belong to fibrous roots, and the adventitious roots are developed, so it is wrong;

C, rice is a green flowering plant, so it can blossom and bear fruit, so it is correct;

D, rice belongs to monocotyledonous plants, and there is only one cotyledon in the seed, so it is wrong.

So choose: C.