Xiancao, also known as Xiancao and Mesona blume, is an annual herbaceous perennial plant of Mesona blume in Labiatae, which can benefit for many years if planted for one year, with a height of 100 cm. The leaves are opposite and bloom in late autumn. Born in ditches and dry sandy grass.

The cymbals are arranged in a terminal raceme with a length of 2~8 cm; Corolla is white or reddish, 3~3.5 mm long, upper lip is wide and big, with 4 teeth, middle 2 teeth are not obvious, and lower lip is boat-shaped. It has the functions of clearing away summer heat, relieving fever and diuresis.

Herbs, erect or creeping. The height of the stem is 15- 100 cm, the branches are more or less branched, the stems and branches are quadrangular, sometimes grooved, and the long hairs or fine bristles are shed. Leaves narrowly ovoid to broadly ovoid or suborbicular, 2-5 cm long and 0.8-2.8 cm wide, smaller on branchlets, acute or obtuse at the apex, acute or obtuse at the base, or sometimes rounded, with shallow or deep serrations at the edge, papery or nearly membranous, with fine bristles or pilose on both sides, or only along the lower veins, or becoming hairless, with 6-7 pairs of lateral veins and middle ribs. Petiole is 2- 15 mm long and is spreading pilose. Immortal grass

There are many cymbals, which form discontinuous or nearly continuous terminal racemes. This inflorescence is 2- 10( 13) cm long, upright or obliquely upward, with short stalks; Bracts are round or rhombic-ovoid, sparsely lanceolate, slightly longer or shorter than flowers, with short or long caudate spikes, usually colored; Pedicel slender, 3-4(5) mm long, short-haired. Calyx blooms in a clock shape, 2-2.5 mm long, densely white and sparsely pilose, with inconspicuous veins, 2-lipped, 3-lobed upper lip, extra-large middle lobe, acute or obtuse apex, small side lobes, entire lower lip, and occasional slight defects. When fruit is in the shape of calyx tube or altar tube, it is 3-5 mm long, and 10 vein and most transverse veins are extremely obvious.