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

aquatic plant Aquatic plants are plants that have adapted to living in aquatic environments (saltwater or freshwater). They are also referred to as hydrophytes or macrophytes to distinguish them from algae and other microphytes. A macrophyte is a plant that ...

in the pickerel-weed family (

Pontederiaceae Pontederiaceae is a 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 commelinid clade, in ...

). 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. Although the term specifically excludes seawater and brackish water, it does include ...

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 An inflorescence is a group or cluster of flowers arranged on a stem that is composed of a main branch or a complicated arrangement of branches. Morphologically, it is the modified part of the shoot of seed plants where flowers are formed o ...

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 (plural ''stamina'' or ''stamens'') is the pollen-producing reproductive organ of a flower. Collectively the stamens form the androecium., p. 10 Morphology and terminology A stamen typically consists of a stalk called the filame ...

s with curling anthers and one yellow

style Style is a manner of doing or presenting things and may refer to: * Architectural style, the features that make a building or structure historically identifiable * Design, the process of creating something * Fashion, a prevailing mode of clothing ...

. 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, fungi, or animals. Plant galls are abnormal outgrowths of plant tissues, similar to be ...

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

References

External links

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