''Aegialitis'' is a

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nom ...

of two shrubby

mangrove A mangrove is a shrub or tree that grows in coastal saline or brackish water. The term is also used for tropical coastal vegetation consisting of such species. Mangroves are taxonomically diverse, as a result of convergent evolution in severa ...

species, with one native to

Southeast Asia Southeast Asia, also spelled South East Asia and South-East Asia, and also known as Southeastern Asia, South-eastern Asia or SEA, is the geographical south-eastern region of Asia, consisting of the regions that are situated south of mainland ...

and the other native to

Australia Australia, officially the Commonwealth of Australia, is a sovereign country comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands. With an area of , Australia is the largest country by ...

and

Papua New Guinea Papua New Guinea (abbreviated PNG; , ; tpi, Papua Niugini; ho, Papua Niu Gini), officially the Independent State of Papua New Guinea ( tpi, Independen Stet bilong Papua Niugini; ho, Independen Stet bilong Papua Niu Gini), is a country i ...

Description

The two species of the genus are woody mangrove shrubs or small trees that grow up to 2 to 3 m tall. The

deciduous In the fields of horticulture and Botany, the term ''deciduous'' () means "falling off at maturity" and "tending to fall off", in reference to trees and shrubs that seasonally shed leaves, usually in the autumn; to the shedding of petals, ...

species have leafy stems with leathery leaves arranged alternately or spirally. The

leaf margin A leaf ( : leaves) is any of the principal appendages of a vascular plant stem, usually borne laterally aboveground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", while the leaves, ste ...

s are entire and have parallel veins. The

hermaphroditic In reproductive biology, a hermaphrodite () is an organism that has both kinds of reproductive organs and can produce both gametes associated with male and female sexes. Many taxonomic groups of animals (mostly invertebrates) do not have s ...

flowers are pollinated by

Hymenoptera Hymenoptera is a large order of insects, comprising the sawflies, wasps, bees, and ants. Over 150,000 living species of Hymenoptera have been described, in addition to over 2,000 extinct ones. Many of the species are parasitic. Females typic ...

Lepidoptera Lepidoptera ( ) is an order of insects that includes butterflies and moths (both are called lepidopterans). About 180,000 species of the Lepidoptera are described, in 126 families and 46 superfamilies, 10 percent of the total described speci ...

, and

Diptera Flies are insects of the order Diptera, the name being derived from the Greek δι- ''di-'' "two", and πτερόν ''pteron'' "wing". Insects of this order use only a single pair of wings to fly, the hindwings having evolved into advanced ...

. Flowers are arranged in terminal cymose racemous

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 forme ...

s. Individual flowers have five

sepal A sepal () is a part of the flower of angiosperms (flowering plants). Usually green, sepals typically function as protection for the flower in bud, and often as support for the petals when in bloom., p. 106 The term ''sepalum'' was coine ...

s arranged in a fused tube around the white gamopetalous

corolla Corolla may refer to: *Corolla (botany), the petals of a flower, considered as a unit *Toyota Corolla, an automobile model name *Corolla (headgear) A ''corolla'' is an ancient headdress in the form of a small circlet or crown.androecium 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 fil ...

consists of five

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 fila ...

s that are attached near the base of the corolla tube. The superior

gynoecium Gynoecium (; ) is most commonly used as a collective term for the parts of a flower that produce ovules and ultimately develop into the fruit and seeds. The gynoecium is the innermost whorl of a flower; it consists of (one or more) '' pist ...

has five

carpel Gynoecium (; ) is most commonly used as a collective term for the parts of a flower that produce ovules and ultimately develop into the fruit and seeds. The gynoecium is the innermost whorl of a flower; it consists of (one or more) '' pistils' ...

s, each with a 1-celled

pistil Gynoecium (; ) is most commonly used as a collective term for the parts of a flower that produce ovules and ultimately develop into the fruit and seeds. The gynoecium is the innermost whorl of a flower; it consists of (one or more) '' pistils ...

and

unilocular A locule (plural locules) or loculus (plural loculi) (meaning "little place" in Latin) is a small cavity or compartment within an organ or part of an organism (animal, plant, or fungus). In angiosperms (flowering plants), the term ''locule'' usu ...

ovaries The ovary is an organ in the female reproductive system that produces an ovum. When released, this travels down the fallopian tube into the uterus, where it may become fertilized by a sperm. There is an ovary () found on each side of the body. T ...

. Fruit are

dehiscent Dehiscence is the splitting of a mature plant structure along a built-in line of weakness to release its contents. This is common among fruits, anthers and sporangia. Sometimes this involves the complete detachment of a part; structures that op ...

and have a spongy

mesocarp Fruit anatomy is the plant anatomy of the internal structure of fruit. Fruits are the mature ovary or ovaries of one or more flowers. They are found in three main anatomical categories: aggregate fruits, multiple fruits, and simple fruits. Agg ...

. Unlike other mangrove species, the members of ''Aegialitis'' generally do not have

aerial root Aerial roots are roots above the ground. They are almost always adventitious. They are found in diverse plant species, including epiphytes such as orchids (''Orchidaceae''), tropical coastal swamp trees such as mangroves, banyan figs (''Fic ...

s.Australian Institute of Marine Science. (2003)
Club Mangrove
. ''Field Guide to the Mangroves of Queensland''. Accessed online: 5 January 2009.

Distribution and habitat

The two species of the genus are native to Southeast Asia and Australia, but their distribution ranges do not overlap. ''A. annulata'' is found along the northern coasts of Australia from

Western Australia Western Australia (commonly abbreviated as WA) is a state of Australia occupying the western percent of the land area of Australia excluding external territories. It is bounded by the Indian Ocean to the north and west, the Southern Ocean to t ...

through the

Northern Territory The Northern Territory (commonly abbreviated as NT; formally the Northern Territory of Australia) is an Australian territory in the central and central northern regions of Australia. The Northern Territory shares its borders with Western Aust ...

and into

Queensland ) , nickname = Sunshine State , image_map = Queensland in Australia.svg , map_caption = Location of Queensland in Australia , subdivision_type = Country , subdivision_name = Australia , established_title = Before federation , establishe ...

and along the coastline of Papua New Guinea. ''A. rotundifolia'' is found on the shorelines of the

Andaman Sea The Andaman Sea (historically also known as the Burma Sea) is a marginal sea of the northeastern Indian Ocean bounded by the coastlines of Myanmar and Thailand along the Gulf of Martaban and west side of the Malay Peninsula, and separated fro ...

and the

Bay of Bengal The Bay of Bengal is the northeastern part of the Indian Ocean, bounded on the west and northwest by India, on the north by Bangladesh, and on the east by Myanmar and the Andaman and Nicobar Islands of India. Its southern limit is a line bet ...

from

Orissa Odisha (English: , ), formerly Orissa ( the official name until 2011), is an Indian state located in Eastern India. It is the 8th largest state by area, and the 11th largest by population. The state has the third largest population of S ...

Mergui Myeik (, or ; mnw, ဗိက်, ; th, มะริด, , ; formerly Mergui, ) is a rural city in Tanintharyi Region in Myanmar (Burma), located in the extreme south of the country on the coast off an island on the Andaman Sea. , the estimat ...

and on the

Andaman Islands The Andaman Islands () are an archipelago in the northeastern Indian Ocean about southwest off the coasts of Myanmar's Ayeyarwady Region. Together with the Nicobar Islands to their south, the Andamans serve as a maritime boundary between t ...

.Saenger, P. (2002).
Mangrove Ecology, Silviculture, and Conservation
'' Springer Publishing. pp. 26. .Weber-El Ghobary, Magda O. (1984). The systematic relationships of ''Aegialitis'' (Plumbaginaceae) as revealed by pollen morphology. ''Plant Systematics and Evolution'', 144(1): 53-58. The distribution of these two species with respect to the other members of the Plumbaginaceae is suggestive of the evolutionary history and

phylogenetic In biology, phylogenetics (; from Greek φυλή/ φῦλον [] "tribe, clan, race", and wikt:γενετικός, γενετικός [] "origin, source, birth") is the study of the evolutionary history and relationships among or within groups ...

placement of ''Aegialitis''. Several authors have discovered evidence for three distinct southern migrations of this mostly

Northern Hemisphere The Northern Hemisphere is the half of Earth that is north of the Equator. For other planets in the Solar System, north is defined as being in the same celestial hemisphere relative to the invariable plane of the solar system as Earth's Nort ...

family, the first of which remained isolated and evolved into the existing members of this genus. This hypothesized migration and evolutionary history explains the more primitive breeding system characteristics and morphology in this genus in relation to the rest of the family.Lledó, M. D., Karis, P. O., Crespo, M. B., Fay, M. F., and Chase, M. W. (2001). Phylogenetic position and taxonomic status of the genus ''Aegialitis'' and subfamilies Staticoideae and Plumbaginoideae (Plumbaginaceae): evidence from plastid DNA sequences and morphology. ''Plant Systematics and Evolution'', 229: 107-124. As with other mangrove species, the habitat preferred by the members of this genus are sandy or rocky soils in the more saline environment of the mangroves toward the sea. The species are thus

halophytic A halophyte is a salt-tolerant plant that grows in soil or waters of high salinity, coming into contact with saline water through its roots or by salt spray, such as in saline semi-deserts, mangrove swamps, marshes and sloughs and seashores. ...

Botanical history and taxonomy

The genus ''Aegialitis'' was described by Robert Brown in his 1810 work ''

Prodromus Florae Novae Hollandiae et Insulae Van Diemen ''Prodromus Florae Novae Hollandiae et Insulae Van Diemen'' (Prodromus of the Flora of New Holland and Van Diemen's Land) is a flora of Australia written by botanist Robert Brown and published in 1810. Often referred to as ''Prodromus Flora Novae ...

'' when he described the single species ''A. annulata''. The second species was described by

William Roxburgh William Roxburgh FRSE FRCPE FLS (3/29 June 1751 – 18 February 1815) was a Scottish surgeon and botanist who worked extensively in India, describing species and working on economic botany. He is known as the founding father of Indian botany. ...

in the 1830s. A genus of

grass Poaceae () or Gramineae () is a large and nearly ubiquitous family of monocotyledonous flowering plants commonly known as grasses. It includes the cereal grasses, bamboos and the grasses of natural grassland and species cultivated in lawns a ...

es was given the same genus name in 1820 by

Carl Bernhard von Trinius Carl Bernhard von Trinius (6 March 1778, Eisleben – 12 March 1844, St. Petersburg) was a German-born botanist and physician. He studied medicine at several universities, earning his medical doctorate at the University of Göttingen in 1802. ...

and later renamed ''

Rostraria ''Rostraria'' is a genus of plants in the grass family, native primarily to Eurasia and North Africa with one species native to South America. Hairgrass is a common name. These grasses are sometimes included in genus ''Koeleria''. ; Species * ' ...

''.Flora of Pakistan.
''Aegialitis''
Accessed online 5 January 2009. There have been several opinions on the proper placement of the genus in relation to the rest of the Plumbaginaceae, though most authors have noted its distinct characteristics make it difficult to place properly. In 1968

Igorj Alexandrovich Linczevski Igor Alexandrovitch Lintchevski (russian: Игорь Александрович Линчевский) (16 June 1908 – 18 July 1997) was a Russian botanist. Biography Igor Lintchevski was born in Leningrad in a teaching family. His childhood a ...

suggested that the genus be included in its own

monotypic In biology, a monotypic taxon is a taxonomic group (taxon) that contains only one immediately subordinate taxon. A monotypic species is one that does not include subspecies or smaller, infraspecific taxa. In the case of genera, the term "unispe ...

family, the Aegialitidaceae. The Plumbaginaceae has historically been divided into either two subfamilies or two tribes and each approach has offered a different perspective of the proper taxonomic relationship in the family. Through

cladistic analysis Cladistics (; ) is an approach to biological classification in which organisms are categorized in groups ("clades") based on hypotheses of most recent common ancestry. The evidence for hypothesized relationships is typically shared derived chara ...

using both genetic and morphological characteristics, studies have concluded that ''Aegialitis'' is the sister

taxon In biology, a taxon ( back-formation from '' taxonomy''; plural taxa) is a group of one or more populations of an organism or organisms seen by taxonomists to form a unit. Although neither is required, a taxon is usually known by a particular n ...

to the rest of its subfamily (Staticoideae) and thus has been assigned to the monotypic tribe Aegialitideae, which is sister to the tribe Staticeae (including the genera ''

Acantholimon ''Acantholimon'' (prickly thrift) is a genus of small flowering plants within the plumbago or leadwort family, Plumbaginaceae. They are distributed from southeastern Europe to central Asia and also in South America, but also cultivated elsewh ...

'', ''

Armeria ''Armeria'' is a genus of flowering plants. These plants are sometimes known as "lady's cushion", "thrift", or "sea pink" (the latter because as they are often found on coastlines). The genus counts over a hundred species, mostly native to the ...

'', '' Goniolimon'', '' Limoniastrum'', and '' Limonium''). The genus name, ''Aegialitis'', derives from the Greek, ''aegialos'', ("seashore"), referring to where species of this genus are found.

References

External links

* {{Taxonbar, from=Q4687565 Plumbaginaceae Mangroves Caryophyllales genera Taxa named by Robert Brown (botanist, born 1773)