Hydrothrix

{{Short description|Genus of flowering plants}}

{{Speciesbox

| image =

| image_caption =

| genus = Heteranthera

| authority = (Hook.f.) M.Pell.

| species = gardneri

| synonyms =

• Hydrothrix gardneri Hook.f.
• Hydrothrix verticillaris Hook.f.
• Hookerina gardneri Kuntze, Rev. Gen. 2: 718. 1891

}}

Hydrothrix Hook.f.{{cite web |url=http://aob.oxfordjournals.org/content/os-1/2/89.extract |archive-url=https://archive.today/20120717113202/http://aob.oxfordjournals.org/content/os-1/2/89.extract |url-status=dead |archive-date=2012-07-17 |title=On Hydrothrix, a new genus of Pontederiaceae |work=oxfordjournals.org}} was previously a monotypic flowering plant genus of Pontederiaceae, but is currently included in a broader and monophyletic Heteranthera.

The highly modified Heteranthera gardneri is a submerged aquatic with a two-flowered pseudanthium found in eastern Brazil. It is used as an aquarium plant.