The Alismatales (alismatids) are an order of flowering plants including about 4500 species. Plants are aquatic or tropical. Some increase some in habitats, in water.

Description

The Alismatales include herbaceous flowering plants of aquatic and marshy habitats, and the sole monocots have proven to have green embryos aside from the Amaryllidaceae. They also incorporate the only marine angiosperms growing entirely submerged, the seagrasses. The blossoms are often arranged in inflorescences and the mature seeds deficiency endosperm.

Both freshwater and marine forms include those with staminate Blossoms that float to the surface where they become and detach from the parent plant pollinated. In the others, pollination occurs underwater, where pollen can form elongated strands. Aquatic species have a juvenile stage that is submerged, and flowers are floating or emergent. Vegetation protrudes from the water, have leaves that are floating, or might be submerged. Collectively, they are generally called”water plantain”.

Categorisation

The Alismatales includes about 165 genera in 13 households, using a cosmopolitan distribution. Phylogenetically, they’re basal monocots, diverging early in development relative to the lilioid and commelinid monocot lineages. Together with the Acorales, the Alismatales is known informally as the alismatid monocots.

Angiosperm Phylogeny Group

The Angiosperm Phylogeny Group system (APG) of 1998 and APG II (2003) delegated the Alismatales into the monocots, which might be thought of as an unranked clade comprising the families listed below. The largest departure from earlier systems is that the addition of family Araceae. In the number of species, the arrangement has increased by its addition. The family Araceae accounts totalling more than two million species. The remaining families contain only about five hundred species, many of which are in smaller families.

The APG III system (2009) differs only in the Limnocharitaceae are combined with the Alismataceae; it was also suggested that the genus Maundia (of the Juncaginaceae) could be separated into a monogeneric family, the Maundiaceae, but the authors noted that more study was necessary before the Maundiaceae might be recognized.

• Alismataceae
• Aponogeton
• Araceae
• Butomaceae
• Cymodoceaceae
• Hydrocharitaceae
• Juncaginaceae
• Posidonia
• Potamogetonaceae
• Ruppia
• Scheuchzeria
• Tofieldiaceae
• Zosteraceae

In APG IV (2016), it was determined that evidence was enough to elevate Maundia to household level as the monogeneric Maundiaceae. The writers considered including some of the orders The Juncaginaceae, but an online poll of users and botanists found little support for this “lumping” approach. Consequently, the family structure for APG IV is: