''Heteranthera dubia'', commonly called water stargrass or grassleaf mudplantain, is a species of

aquatic plant Aquatic plants, also referred to as hydrophytes, are vascular plants and Non-vascular plant, non-vascular plants that have adapted to live in aquatic ecosystem, aquatic environments (marine ecosystem, saltwater or freshwater ecosystem, freshwater ...

in the pickerel-weed family (

Pontederiaceae Pontederiaceae is a Family (biology), family of flowering plants. The APG IV system of 2016 (unchanged from the APG III system of 2009, the APG II system of 2003 and the APG system of 1998) places the family in the order Commelinales, in the co ...

). It is native to North and Central America where it is widespread from Canada to Guatemala. It lives submerged in

freshwater Fresh water or freshwater is any naturally occurring liquid or frozen water containing low concentrations of dissolved salts and other total dissolved solids. The term excludes seawater and brackish water, but it does include non-salty mi ...

such as rivers and lakes. It can be found as deep as 5.5 meters, to as shallow as stranded on the shoreline. It is most abundant in alkaline waters. ''Heteranthera dubia'' is a perennial with much variation in its appearance. The leaves are different sizes and shapes across individuals, partly genetic variation and partly response to water conditions, for example, the speed and turbulence of surrounding currents. Submersed individuals also have a different stem and leaf morphology from those that occur partially or completely out of the water. Its

inflorescence In botany, an inflorescence is a group or cluster of flowers arranged on a plant's Plant stem, stem that is composed of a main branch or a system of branches. An inflorescence is categorized on the basis of the arrangement of flowers on a mai ...

bears a single short-lived flower that blooms in the morning and wilts in the evening. It has six yellow perianth parts each less than a centimeter long spreading from a tubular throat one to seven centimeters long. There are three long, thick yellow

stamen The stamen (: stamina or stamens) is a part consisting of the male reproductive organs of a flower. Collectively, the stamens form the androecium., p. 10 Morphology and terminology A stamen typically consists of a stalk called the filament ...

s with curling anthers and one yellow

style Style, or styles may refer to: Film and television * ''Style'' (2001 film), a Hindi film starring Sharman Joshi, Riya Sen, Sahil Khan and Shilpi Mudgal * ''Style'' (2002 film), a Tamil drama film * ''Style'' (2004 film), a Burmese film * '' ...

. The fruit is a capsule containing many winged seeds. The plant sometimes has

gall Galls (from the Latin , 'oak-apple') or ''cecidia'' (from the Greek , anything gushing out) are a kind of swelling growth on the external tissues of plants. Plant galls are abnormal outgrowths of plant tissues, similar to benign tumors or war ...

s in its tissue, which are caused by the parasitic fungus '' Membranosorus heterantherae''.

References

External links

Jepson Manual Treatment
Pontederiaceae Freshwater plants Flora of Northern America Flora of Guatemala {{Commelinales-stub