Japanese name: ヤマジソ（山紫蘇） Scientific name:Mosla japonica var. japonica
[Overview]
An annual 5–30 cm tall, found on sunny bare ground in hills and mountains.
It contains thymol and is fragrant.
The stem is branched, square in cross section, and has fine, short, white hairs that curve downward.
The stem is often tinged with reddish purple.
The leaves are simple and opposite, ovate to narrowly ovate, 1–3 cm long and 0.5–1.7 cm wide, with sparse soft simple hairs on both surfaces.
The leaf margins have low teeth.
The petiole is 0.1–0.5 cm long.
The flowers are borne in pairs at each node and form dense spikes 1–4 cm long.
The flowers are pale reddish purple and two-lipped, with the upper lip 3-lobed and the lower lip 2-lobed.
The bracts are ovate to broadly ovate, and those at the base of the spike are longer than the calyx.
The fruit is a schizocarp with a net-like pattern on the surface.
[Uses]
The essential oil is called Yamajiso oil and is used medicinally.
