Japanese name: ミズトラノオ（水虎尾） Scientific name:Pogostemon yatabeanus
[Overview]
A perennial 30–60 cm tall, found in wet lowlands such as marshes, fallow rice fields, and the edges of reservoirs.
It sends out creeping underground stems and stolons, and the erect stems grow in clumps.
The stem is soft, almost unbranched, and hairless.
Leaves are simple, in whorls of 3–4, linear, 3–7 cm long, with blunt tips, soft in texture, and almost sessile.
The leaf margins are entire or have very indistinct teeth.
A single spike 2–8 cm long and about 1.2–1.5 cm in diameter at the stem tip bears densely packed flowers.
The flowers are small and lip-shaped with 4 lobes.
The flowers are inconspicuous, but there are 4 pale reddish-purple stamens whose filaments have long dense hairs in the middle, making them feathery, and because they protrude from the flower, the flower spike looks like a brush.
The calyx is 5-lobed, and soft hairs grow on it and on the bracts.
The fruit is a schizocarp.
