Description
This light green lawn-forming Helanthium (Chain sword) is great for aquascaping. It is also sold under the names Echinodorus tenellus, E. tenellus "Green" and Helanthium tenellum "Broad Leaf".
The plantlets are best planted into the substrate individually at a small distance. Under strong light (ideally 0.5 watts/litre or more) and a good nutrient and CO2 supply the plant will readily reproduce by forming long runners with many plantlets. Should it grow too fast, just cut off the new runners. If the lawn has grown too dense you ought to thin it from time to time.
Helanthium tenellum "parvulum" is a light green, usually smaller and wider-leaved form of Helanthium tenellum (= Echinodorus tenellus). It was probably first imported from North America. Decades ago, this was the aquarium plant generally known as Echinodorus tenellus, today it is only rarely cultivated any more. Its submersed leaves are always light green, never reddish, up to a little over 2 mm wide and widest below the middle. The plant usually sold under the name H. tenellum today was imported from the American tropics (Brazil?), and its submersed leaves are generally of an olive green to reddish colour, longer and narrower (up to around 1.5 mm) that are widest above the middle (see Helanthium tenellum). Its emersed, flowering form also differs clearly from H. tenellum "parvulum". A well-growing clone of H. tenellum "parvulum" has spread in the hobby, under the erroneous name "Ranalisma rostrata". True Ranalisma rostratum from Asien indeed looks rather like the submersed form of Helanthium tenellum, its emersed form, however, differs clearly (see Ranalisma rostratum).
Source
Flowgrow
Characteristic
Also known as Helanthium tenellum 'Broad Leaf'
Grasslike ground-covering plant
Light to medium green colours
Wider leaves than Helanthium tenellum
Synonyms
Echinodorus parvulus Engelm., Helanthium parvulum (Engelm.) Small, Echinodorus tenellus, nordamerikanische Form, Echinodorus tenellus 'Broad Leaf', Helanthium tenellum 'Broad Leaf', Echinodorus tenellus 'Green'
Complete Botanical Name
Helánthium tenéllum (Mart. ex Schult. f.) J. G. Sm.
Family
Alismataceae
Genus
Helanthium
Misapplied Names
Ranalisma rostrata
Category
Middle Ground
Difficulty
medium
Growth
medium
Carbon Dioxide
need
pH Value
5-7
Temperature Tolerance
10-30℃
Carbonate Hardness
0-14 dKH
General Hardness
0-30 °dGH
Propagation
Runners
Can Grow Emersed?
yes
Aquascaping
forms a grass-like lawn
