Dwarf Sagitaria will produce small white flowers similar but different than the eelgrass flower. Dwarf Sagittaria and short eel grass species look a lot alike. Eel grass when it flowers will have the flower on the end of the elongated ovary on a corkscrew like stem. There are several short versions or species of eel grass.

http://www.plantsrescue.com/sagittaria-subulata/
http://www.flowgrow.de/db/aquaticplants/sagittaria-subulata

eel grass flower
http://www.floridaaquatic.com/aquarium_plant_vallisneria_spiralis.html

see Phil Edwards post in this thread.
http://www.aquaticplantcentral.com/forumapc/aquascaping/58638-my-124g-planted-tank-4.html

aka Pond Doctor & Dr. Perca Read Pond Boss Magazine -
America's Journal of Pond Management