Lobelia cardinalis is agreen stem plant characterized by it's oval leaves when grown submerged.
When grown emersed flowers and leaves can turn a bright red.
Lobelia cardinalis  is widely used as a midground or foreground plant in Dutch style aquariums because of its interesting leaf shape and bright green foliage.
Doesn't grow as quickly as other aquarium plants.
Levels of light exposure can affect the appearance. High light  will give it a more bushy, compact appearance whereas low lighting will make it grow taller and with less foliage. 
You will receive 1 rhizome atleast 4 inches long.