PPT Ploski rvi ali ploskavci (Plathelmintes) PowerPoint Presentation [PDF] Vertebrate Palaeontology by Michael J. Benton eBook Perlego Nematoda The Excretory System Proboscis worm Glycera dibranchiata Britannica. Gratiola viscidula originates from Northern America and is relatively new to the aquatic hobby. The somewhat thorny appearance of the submersed form makes it very distinct and easily recognisable. It is quite easy to grow and prefers good light. By regular trimming it can be kept very low, almost carpeting, but will also present itself well as a fore mid ground cushion plant. Each stem is approximately 1 2 cm wide and can become 10+ cm tall. The stem willingly branches and spreads giving a very dense appearance to the plant.. Product Details: Type: Stem Growth: Slow Light: Medium Origin: North America Height: 3 10+ CO2: Medium