1、 Stem difference

Xianfeng grass is an annual herb, about 90cm high, with many branches, square stems, green color, and most of the nodes will have lavender. Bidens bipinnata stem is relatively upright, about 30-100 cm high, blunt quadrangular, and the upper part will have sparse pilose or glabrous

2、 Blade difference

The leaves of Xianfeng grass are opposite. The color is thick green on the surface and gray green on the back. It is very shiny. It is about 3cm long and similar in size. The leaves under the stem of Bidens bipinnata are smaller, the terminal leaves are larger and of different sizes, the larger ones can reach 3.5-7 cm, and the middle parts on both sides are about 2-4.5 cm long

3、 The difference between flowers

Xianfeng grass is in the shape of head, and its inflorescences are arranged in the shape of fimbria, axillary or terminal. It has long stem, green involucre, 4-7 white tongue flowers and yellow tubular flowers in the middle. Bidens, though similar in color, has no glossy flowers