Aponogeton rigidifolius

Aponogeton rigidifolius
Scientific classification
Kingdom:	Plantae
Clade:	Angiosperms
Clade:	Monocots
Order:	Alismatales
Family:	Aponogetonaceae
Genus:	Aponogeton
Species:	A. rigidifolius
Binomial name
Aponogeton rigidifolius H. Bruggen

Aponogeton rigidifolius is native to Sri Lanka. In the wild it grows in deep water at temperatures of 68 to 77 °F (20 to 25 °C) in sandy soil with the water pH at 7.2.

The creeping rhizome is cylindrical and about 5 inches (13 cm) thick. The leaves stay submerse, are firm (almost leather-like and seem immune to most fish and snails) about 8 to 23 inches (20 to 58 centimetres) long and 1 to 1.6 inches (2.5 to 4.1 centimetres) wide. The margins of the leaves are flat to slightly undulate with a distinct midrib. In colour they are a dark green to reddish colour. The inflorescence has a single spike with white flowers and small fruits.

This species is unique amongst the Aponogetons in having an elongated rhizome rather than a tuber; the rhizome creeps along the surface, and from it new leaves sprout. This rhizome can be divided. It needs no rest period but is slow growing, though tough once established. It needs only a moderate light, tropical temperatures, and will tolerate harder water than most other Aponogetons. It is not commonly available but a good plant for the middle to background of an aquarium. It flowers rarely in aquariums.

...
Wikipedia