Barclaya longifolia

Barclaya longifolia is a species of perennial aquatic plant native to the region of Indo-China to Northwest Peninsular Malaysia.

Vegetative characteristics
Barclaya longifolia is a submerged, perennial, aquatic herb with ovoid, tuberous, stoloniferous, 2-3 cm long, and 0.5-1.5 cm wide rhizomes. The linear-lanceolate, 12-30 cm long and 2-5 cm wide leaves with an obtuse apex, and a cordate base have an undulate margin. The abaxial leaf surface displays red colouration. The petioles are 6-25 cm long.

Generative characteristics
The submerged and cleistogamous, or emerged and chasmogamous, 4-6 cm wide flowers are attached to 5-30 cm long peduncles with numerous trichomes. The sepals are 1.5-2.5 cm long, and 0.5-0.6 cm wide. The syncarpous, inferior gynoecium consists of 8-14 carpels. The globose, reddish green to whitish, 1-2 cm wide fruit bears 1mm long, and 0.5 mm wide, echinate, brownish red, globose seeds without an arillus.

Cytology
The diploid chromosome count is 2n = 36. The chloroplast genome is 158359 bp long.

Vegetative reproduction
The rhizomes are stoloniferous.

Generative reproduction
Barclaya longifolia can produce autogamous, submerged, cleistogamous flowers,  as well as emergent chasmogamous flowers.

Publication
It was first described by Nathaniel Wallich in 1827. It is the type species of its genus.

Type specimen
The type specimen was collected by Wallich in Rangoon, Myanmar in August 1826.

Etymology
The specific epithet longifolia, from the Latin longus meaning "long", and folius meaning "leaf", means long-leaved.

Conservation
The IUCN conservation status is least concern (LC). It may be endangered in Peninsular Malaysia. In India, it is a rare species.

Habitat
It occurs in quickly flowing rivers, streams, and stagnant pools. Disturbance of the substrate by wild boar may be beneficial for the establishment of Barclaya longifolia seedlings in their natural habitat.

Cultivation
It is a popular aquarium plant. It can be easily cultivated in a mixture of pH-neutral, loamy and mineral soils at temperatures of 26-29°C.