Ottelia

{{Short description|Genus of flowering plants}} {{automatic taxobox | image = Ottelia_alismoides_W_IMG_0915.jpg | image_caption = ''Ottelia alismoides'' | taxon = Ottelia | authority = Pers. 1805 not R.Hedw. 1806 | synonyms_ref = <ref name=r/> | synonyms = *''Damasonium'' Schreb. 1789, illegitimate homonym, not Mill. 1754 (Hydrocharitaceae) nor Adans. 1789 (syn of ''Limnocharis'' in Alismataceae) *''Hymenotheca'' Salisb. *''Boottia'' Wall. *''Oligolobos'' Gagnep. *''Xystrolobos'' Gagnep. *''Beneditaea'' Toledo }}

'''''Ottelia''''' is a genus of an aquatic plant family Hydrocharitaceae described as a genus in 1805.<ref>[https://www.biodiversitylibrary.org/page/235185#page/412/mode/1up Persoon, Christiaan Hendrik. 1805. Synopsis plantarum, seu Enchiridium botanicum, complectens enumerationem systematicam specierum hucusque cognitarum 1: 400] in Latin</ref><ref>Cook, C.D.K., Symoens, J.-J. Urmi- Konig, K. (1984) [http://www.sciencedirect.com/science/article/pii/0304377084900688 A revision of the genus ''Ottelia'' (Hydrocharitaceae). 1. Generic considerations] ''Aquatic Botany'' '''18:''' 263-274</ref> The genus is native to tropical and subtropical regions of Africa, Asia, South America, and Australia.<ref>{{Cite web |title=Ottelia Pers. |url=http://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:30413326-2 |access-date=2022-11-09 |website=Plants of the World Online |language=en}}</ref><ref name=":0">Cook, C.D.K. and Urmi- Konig, K. (1984) [http://www.sciencedirect.com/science/article/pii/0304377084900330 A revision of the genus ''Ottelia'' (Hydrocharitaceae). 2. The species of Eurasia, Australasia and America] ''Aquatic Botany'' '''20:''' 131–177</ref>

== Description == The genus is highly variable, with a variety of features.<ref name=":1">{{Cite journal |last1=Li |first1=Zhi-Zhong |last2=Lehtonen |first2=Samuli |last3=Martins |first3=Karina |last4=Gichira |first4=Andrew W. |last5=Wu |first5=Shuang |last6=Li |first6=Wei |last7=Hu |first7=Guang-Wan |last8=Liu |first8=Yan |last9=Zou |first9=Chun-Yu |last10=Wang |first10=Qing-Feng |last11=Chen |first11=Jin-Ming |date=2020-11-01 |title=Phylogenomics of the aquatic plant genus Ottelia (Hydrocharitaceae): Implications for historical biogeography |url=https://www.sciencedirect.com/science/article/pii/S1055790320302116 |journal=Molecular Phylogenetics and Evolution |language=en |volume=152 |article-number=106939 |doi=10.1016/j.ympev.2020.106939 |pmid=32791299 |bibcode=2020MolPE.15206939L |s2cid=221121993 |issn=1055-7903|url-access=subscription }}</ref> It contains aquatic herbs with crowded leaves. Some of the leaves are held on short stems. Others float on long stems. The rooting stem is long.<ref name="SAGenera">{{Cite book |last=Phillips |first=Edwin Percy |title=The genera of South African flowering plants |publisher=Government Printer |year=1951 |publication-place=South Africa}}</ref>

The flowers are held in a herbaceous bract that is many nerved and has two to six clear ribs. The tubular spathe is shortly divided into two.<ref name="SAGenera" />

Each flower has two rows of a trimerous perianth held above the beak of the ovary. The rigid outer layer is oblong or linear. The larger inner layer is petal-like with a fleshy appendage at the base.<ref name="SAGenera" /> There are six or more stamens, often with flattened filaments.<ref name="SAGenera" /> The ovary is oblong and beaked with strongly developed placentas dividing it into six chambers that contain many ovules. There are six linear styles that are partially split in two.<ref name="SAGenera" />

The tapering oblong fruits are included in the floral bract and have three to six wings. They contain numerous small, oblong seeds.<ref name="SAGenera" />

It has been suggested that this genus should be divided into two subgenera and four sections:<ref name=":2">{{Cite journal |last=Hen |first=Li |date=1981 |title=Classification, distribution and phylogeny of the genus Ottelia |journal=Journal of Systematics and Evolution |volume=19 |issue=1 |pages=29–42}}</ref>

* '''Subgenus Ottelia''' has bisexual flowers. ** '''Section Ottelia:''' The spathes have a single flower and six to nine carpels in the ovary. ** '''Section Oligolobos:''' The spathes have many flowers and an ovary with three carpels. * '''Subgenus Boottia''' has unisexual flowers. The male spathes have one to many flowers while the female spathes always have many flowers. ** '''Section Boottia''': The males spathes have one flower and the ovaries of the female flowers have nine to fifteen carpels. ** '''Section Xystrolobos''': The female spathes have two to many flowers and an ovary with three or nine carpels.

== Distribution == This genus is found throughout the Paleotropics, from Africa to Asia to Australia and New Caledonia and to Brazil.<ref name=":2" /> The areas with the highest diversity occur in central Africa (about 13 species) and south east Asia (about 8 species).<ref name=":0" /><ref name=":1" /> They are mostly found growing in lakes, slow flowing creeks and rivers.<ref name=":3">{{Cite journal |last1=Ngarega |first1=Boniface K. |last2=Nzei |first2=John M. |last3=Saina |first3=Josphat K. |last4=Halmy |first4=Marwa Waseem A. |last5=Chen |first5=Jin-Ming |last6=Li |first6=Zhi-Zhong |date=2022-09-01 |title=Mapping the habitat suitability of Ottelia species in Africa |journal=Plant Diversity |language=en |volume=44 |issue=5 |pages=468–480 |doi=10.1016/j.pld.2021.12.006 |issn=2468-2659 |pmc=9512647 |pmid=36187550|bibcode=2022PlDiv..44..468N }}</ref>

== Phylogenomics and evolution == Originating in the mid Miocene, this genus now consists of two major clades that correspond to the two major centers of diversity - Africa and Asia. Morphological evidence suggests that this genus originated in Africa. It then spread to South America and Australasia via the ocean, and then from Australasia to Asia.<ref name=":1" />

Global cooling, the development of the East Asian monsoon climate and tectonic movement likely aided diversification in China. The movement of the Yunnan-Guizhou Plateau Pin the liocenehas been suggested to explain the high endemism of Chinese species of ''Ottelia''.<ref name=":1" />

== Species == This genus is the second largest in its family (Hydrocharitaceae).<ref name=":1" /> The following species are accepted:<ref name="r">{{Cite web |title=World Checklist of Selected Plant Families: Royal Botanic Gardens, Kew |url=http://apps.kew.org/wcsp/namedetail.do?name_id=308352 |access-date=2017-02-01 |website=apps.kew.org |language=en-GB}}</ref> {{columns-list|colwidth=30em|# ''Ottelia acuminata'' (Gagnep.) Dandy - S China # ''Ottelia alismoides'' (L.) Pers. - Khabarovsk, Primorye, China, Indian Subcontinent, SE Asia, New Guinea, Solomon Is, N Australia # ''Ottelia balansae'' (Gagnep.) Dandy - S China, Vietnam # ''Ottelia brachyphylla'' (Gürke) Dandy - Sudan # ''Ottelia brasiliensis'' (Planch.) Walp. - Brazil, Paraguay, NE Argentina # ''Ottelia cordata'' (Wall.) Dandy - Hainan, Thailand, Myanmar, Cambodia # ''Ottelia cylindrica'' (T.C.E.Fr.) Dandy - Zaïre, Zambia, Angola # ''Ottelia emersa'' Z.C.Zhao & R.L.Luo - Guangxi # ''Ottelia exserta'' (Ridl.) Dandy - from Somalia to Cape Province # ''Ottelia fengshanensis'' Z.Z.Li, S.Wu & Q.F.Wang - from southeast China # ''Ottelia fischeri'' (Gürke) Dandy - from Kenya to Mozambique # ''Ottelia guanyangensis'' Z.Z.Li, Q.F.Wang & S.Wu - from Southeast China # ''Ottelia kunenensis'' (Gürke) Dandy - Zambia, Angola, Botswana, Namibia # ''Ottelia lisowskii'' Symoens - Zaïre, Zambia # ''Ottelia mesenterium'' (Hallier f.) Hartog - Sulawesi # ''Ottelia muricata'' (C.H.Wright) Dandy - C + S Africa # ''Ottelia obtusifolia'' T.C.E.Fr. - from Zambia and Zaïre # ''Ottelia ovalifolia'' (R.Br.) Rich. - Australia # ''Ottelia profundecordata'' Symoens - from the Central African Republic and Zaïre # ''Ottelia scabra'' Baker - South Sudan, Uganda # ''Ottelia ulvifolia'' (Planch.) Walp. - trop + S Africa, Madagascar # ''Ottelia verdickii'' Gürke - Tanzania, Zaïre, Zambia, Angola }}

== Conservation == The species belonging to this genus are being increasingly negatively impacted by the use and pollution of their water bodies. They have also been declining as a result of climate change. This will continue to occur as climate change accelerates habitat fragmentation and habitat loss due to changing conditions, including increasing water temperatures.<ref name=":3" />

==Gallery== <gallery> Ottelia alismoides - flower view.jpg| Flower of ''Ottelia alismoides'' </gallery>

==References== {{Reflist|30em}}

Category:Ottelia Category:Hydrocharitaceae genera