| Author | (Jacquin) MacMillan | |
| Distribution | Known (collected) only from a single site in the state -- in the New River in Alleghany County, in 1961. Despite it having been collected from at least 35 VA counties, many in the southern Piedmont (not to mention Mountains), the fact that it barely enters the edge of NC is quite striking.
This is a very widespread species, occurring across much of southern Canada and southward to western FL and CA. However, within this huge range it is very scarce south of VA and MO. | |
| Abundance | Very rare, and now considered historical. The NCNHP considers it to be Significantly Rare with a State Rank of SH (Historical). Considering its range in VA, it surely must occur somewhere now in northern NC! | |
| Habitat | This species grows in mostly sluggish water, in a swampy margin of a river in NC; elsewhere also in lakes and ponds. Weakley (2018) mentions it prefers calcareous substrates in its range, but such aquatic sites are extremely rare in NC (discounting limesink ponds in the lower Coastal Plain). | |
| Phenology | Blooms from late July into October, and fruits shortly after blooming. | |
| Identification | This is a very odd flowering plant. There are a number of vascular plants that grow submerged in fresh water in NC, and most of these have linear to filamenous leaves, as this one does. However, most have tiny or basically invisible flowers, such as Myriophyllum species, Proserpinaca species, and Hornleaf Riverweed (Podostemum ceratophyllum). Yet, Water Stargrass has a conspicuous bright yellow 6-pointed star-like flower (6 very narrow tepals) on the water surface that makes it look like no other species when in bloom. These flowers are about 1/2-inch across, not at all a large flower, but one that catches attention on a water surface. Actually, the plant looks a bit like submerged green Spanish-moss (Tillandsia usneoides), which also has a surprisingly "sizable" flower! As it has been found in many southwestern VA counties close to NC, it certainly could be re-found in the northwestern corner of the state, either in the Piedmont or in the mountains. | |
| Taxonomic Comments | None
| |
| Other Common Name(s) | Grassleaf Mud-plantain | |
| State Rank | SH | |
| Global Rank | G5 | |
| State Status | SR-P | |
| US Status | | |
| USACE-agcp | OBL link |
| USACE-emp | OBL link |
