Yep .. pretty much the Rhizome is the stem portion that you see at the bottom. Similar with Java Fern. What most members do is tie it down to a piece of DW or a rock to allow the roots to attach ... give it a couple of weeks at least.
I'm looking to get some Anubias next time I'm at Petco, and I'll look to tie it down to a rock or my DW.
75g Planted Barbs Denison, BlackRuby, Tiger, Albino Tiger, Green Tiger, Cherry, Gold, Checkered, Odessa.
NonBarbs Cardinal, Neon, RummyNose, Bloodfin Tetras, Z. Danios. 1RTS. Amano, Bamboo, Ghost & RCS. 20g Long Shrimp Tank RCS, Tiger, Amano.