''Aegialitis'' is a

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

of two shrubby mangrove 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 United Nations geoscheme for Asia#South-eastern Asia, south-eastern region of Asia, consistin ...

and the other native to

Australia Australia, officially the Commonwealth of Australia, is a Sovereign state, sovereign country comprising the mainland of the Australia (continent), Australian continent, the island of Tasmania, and numerous List of islands of Australia, sma ...

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, aft ...

species have leafy stems with leathery leaves arranged alternately or spirally. The leaf margins are entire and have parallel veins. The hermaphroditic flowers are pollinated by

Hymenoptera Hymenoptera is a large order (biology), order of insects, comprising the sawfly, 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 Par ...

Lepidoptera Lepidoptera ( ) is an order (biology), order of insects that includes butterfly, butterflies and moths (both are called lepidopterans). About 180,000 species of the Lepidoptera are described, in 126 Family (biology), families and 46 Taxonomic r ...

, 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 formed o ...

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 coined b ...

s arranged in a fused tube around the white gamopetalous corolla that has five petals fused into a short tube. The

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 filam ...

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 filame ...

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) ''pistils'' ...

has five carpels, 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. Unlike other mangrove species, the members of ''Aegialitis'' generally do not have aerial roots.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 th ...

through the

Northern Territory The Northern Territory (commonly abbreviated as NT; formally the Northern Territory of Australia) is an states and territories of Australia, Australian territory in the central and central northern regions of Australia. The Northern Territory ...

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 , established_ ...

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 from ...

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 between ...

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 Sch ...

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 estimate ...

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 th ...

.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 o ...

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.

Botanical history and taxonomy

The genus ''Aegialitis'' was described by Robert Brown in his 1810 work '' Prodromus Florae Novae Hollandiae et Insulae Van Diemen'' when he described the single species ''A. annulata''. The second species was described by William Roxburgh 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 an ...

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 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 "unispec ...

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 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 nam ...

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'', ''

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 ''Goniolimon'', sometimes called the statices, are a genus of flowering plants in the leadwort and plumbago family Plumbaginaceae, native to northern Africa, southern Europe, western and central Asia, Siberia, Mongolia and China. Low-lying peren ...

'', ''

Limoniastrum ''Limoniastrum'' is a genus of plants in the family Plumbaginaceae, containing two known species of subshrubs found the Mediterranean region, within Africa and southern Europe. It was published by Fabricius in 1759 in 'Enum. Meth. Pl. Hort. Helm ...

'', and ''

Limonium ''Limonium'' is a genus of 120 flowering plant species. Members are also known as sea-lavender, statice, caspia or marsh-rosemary. Despite their common names, species are not related to the lavenders or to rosemary. They are instead in Plumbag ...

''). 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)