Pogostemon helferi

Pogostemon helferi, also known as dao-noi, is a species of Thai aquatic plant. It is a common ornamental plant in aquariums.

Pogostemon helferi
Scientific classification
Kingdom:	Plantae
Clade:	Tracheophytes
Clade:	Angiosperms
Clade:	Eudicots
Clade:	Asterids
Order:	Lamiales
Family:	Lamiaceae
Genus:	Pogostemon
Species:	P. helferi
Binomial name
Pogostemon helferi Hook.f.

Taxonomy

The type locality is Sangkhla Buri district, Kanchanaburi, Thailand.^[1]

Distribution

Pogostemon helferi is distributed across Myanmar and western Thailand.^[2] A 2005 survey conducted in Thailand found the species in north, north-east, east, and west Thailand. However, a 2007 survey found the species only in the Kanchanaburi province, found near Myanmar.^[2] A 2024 review found the species distribution extending to the Indian Himalayan Region.^[3]

Because of the high demand for the plants in aquarium trade, the species has been declining in population in its natural habitat, with local extinction emerging as a possibility.^[2]

Description

Pogostemon helferi is a common ornamental plant. It is commonly known by its local name, dao-noi, meaning "little star". It is a popular plant in aquariums, and is of high demand in the aquarium trade. As of 2016, the economic value of the production of the species was valued at ฿252,000 whilst the annual market demand was more than ฿500,000.^[2]

The species has dimorphic leaves, two distinct types, the first being emerged, which are less durable, and submerged.^[4] It has irregularly shaped epidermis cells.^[1] Most stocks of the species are harvested from the wild.^[2]