Hydatellaceae is the botanical name for a family of flowering plants containing the genera Hydatella and Trithuria. These small, relatively simple, aquatic plants are found only in Australasia and India. The simple leaves are concentrated around a short stem basally. The plants are submerged and emergent aquatic annuals, rooted in the substrate below the water. The members of this plant family are monoecious and are hydrophilous or autogamous. Flowers are clustered into spikelets. The non-fleshy fruits are follicles or achenes.^[1] A botanical name is a formal name conforming to the ICBN. As with its zoological and bacterial equivalents it may also be called a scientific name. Botanical names may be in one part (genus and above), two parts (species) or three parts (below the rank of species). ... The hierarchy of scientific classification In biological classification, family (Latin: familia, plural familiae) is a rank, or a taxon in that rank. ... Classes Magnoliopsida - Dicots Liliopsida - Monocots The flowering plants (also angiosperms or Magnoliophyta) are one of the major groups of modern plants, comprising those that produce seeds in specialized reproductive organs called flowers, where the ovulary or carpel is enclosed. ... Plant sexuality deals with the wide variety of sexual reproduction systems found across the plant kingdom. ... Hydrophily is a fairly uncommon form of pollination whereby pollen is distributed by the flow of waters, particularly in rivers and streams. ... Self-fertilization (also known as autogamy) occurs in hermaphroditic organisms where the two gametes fused in fertilization come from the same individual. ... This inflorescence of the terrestrial orchid Spathoglottis plicata is a typical raceme. ... In botany, a follicle is a dry fruit which splits along one rupture site in order to release seeds, such as in larkspur, magnolia, banksia, peony and milkweed. ... An achene is a type of simple dry fruit produced by many species of flowering plants. ...

Hydatellaceae was for many years assumed to be close relatives of the grasses and sedges and were often included in the family Centrolepidaceae. However, research by Saarela et al. indicates that the Hydatellaceae is the living sister group of the water lilies (Nymphaeales) and thus represent one of the most ancient lineages of flowering plants.^[2] This realignment represents the first time a plant family has been ejected from the monocots.^[3] families see text Poales is a botanical name at the rank of order. ... genera see text Centrolepidaceae is a botanical name for a family of flowering plants. ... Families Cabombaceae - fanworts Nymphaeaceae - water lilies The Nymphaeales are an order of flowering plants, including two families of aquatic herbs: Family Nymphaeaceae (waterlily family) Family Cabombaceae (fanwort family) Sometimes the Cabombaceae are included within the Nymphaeaceae. ... Classes Magnoliopsida - Dicots Liliopsida - Monocots The flowering plants (also angiosperms or Magnoliophyta) are one of the major groups of modern plants, comprising those that produce seeds in specialized reproductive organs called flowers, where the ovulary or carpel is enclosed. ...

The APG II system, of 2003 (unchanged from the APG system, 1998), recognizes a separate family Hydatellaceae and assigns it to the order Poales in the clade commelinids, in the monocots. The family consists of probably fewer than a dozen species. The Cronquist system, of 1981, also recognised such a family and placed it in its own order Hydatellales, in the subclass Commelinidae in class Liliopsida [=monocotyledons]. Neither of these taxonomic systems has been updated to incorporate the information from the 2007 study that removed Hydatellaceae from the monocots. The Angiosperm Phylogeny Website, however, has now placed Hydatellaceae in the order Nymphaeales,^[4] a classification that was not reported in Saarela et al., which suggested instead a sister-group relationship between Nymphaeales and Hydatellaceae.^[2] A modern system of plant taxonomy, the APG II system of plant classification was published in 2003 by the Angiosperm Phylogeny Group, APG, in Angiosperm Phylogeny Group (2003). ... A modern system of plant taxonomy, the APG system of plant classification was published in 1998 by the Angiosperm Phylogeny Group. ... families see text Poales is a botanical name at the rank of order. ... In plant taxonomy, the name commelinids (plural, not capitalised) is used by the APG II system for a clade within the monocots, which in its turn is a clade within the angiosperms. ... Orders Base Monocots: Acorus Alismatales Asparagales Dioscoreales Liliales Pandanales Family Petrosaviaceae Commelinids: Arecales Commelinales Poales Zingiberales Family Dasypogonaceae Monocotyledons or monocots are a group of flowering plants usually ranked as a class and once called the Monocotyledoneae. ... A system of plant taxonomy, the Cronquist system is a scheme for the classification of flowering plants (or angiosperms). ... Hydatellales is a small order of monocot flowering plants, including one family, the Hydatellaceae. ... Commelinidae is a botanical name at the rank of subclass. ... Liliopsida is the botanical name for a class. ...

References

External links

• Hydatellaceae in L. Watson and M.J. Dallwitz (1992 onwards). The families of flowering plants: descriptions, illustrations, identification, information retrieval. Version: 27th April 2006. http://delta-intkey.com.
• Hydatellaceae photographs
• Hydatellela in western Australia
• Trithuria in western Australia
• NCBI Taxonomy Browser
• links at CSDL
• Original paper recognising the family