Posidoniaceae

Taxonomy

Family name: Posidoniaceae Vines

Synonym(s): [none]

Common name(s): posidonia family

*Number of genera/species: 1/9

List of genera records in GRIN-Global

Disseminule

fruit (dehisced or not) or seed

Description

Fruit dehiscentdehiscent:
(v. dehisce) splitting open at maturity to release contents (of a fruit)
, folliclefollicle:
a dry to (rarely) fleshy fruit derived from a single carpel that opens along a single longitudinal suture; the seeds may be arillate or with a fleshy testa
or indehiscentindehiscent:
not opening on its own, as in a fruit
, drupedrupe:
(indehiscent drupe) a fleshy, indehiscent fruit with one more hard pits enclosing seeds; (dehiscent drupe) a fruit with a dry or fibrous to fleshy or leathery outer husk that early to tardily breaks apart (or opens), exposing one or more nutlike pits enclosing the seeds
, 1.5–40 mm long, oblongoblong:
2D shape—much longer than broad with nearly parallel sides, corners are rounded
to ovateovate:
2D shape—egg-shaped in outline, widest point is towards one end of the organ, the other end tapers gradually, attachment at or near the broad end (compare obovate, ovoid)
, roundround:
2D shape—orbiculate; circular
in transectiontransection:
a cross section; representing a plane made by cutting across an organ at a right angle to its length
, with persistent stylestyle:
in a flower, the narrow and elongated part of the pistil between the stigma and the ovary; sometimes persisting in fruit
, often beakedbeaked:
a usually firm, terminal appendage, sometimes tapered
, one seeded. Pericarppericarp:
fruit wall or fruit coat
black, brown, green to yellow, shinyshiny:
uniformly reflecting a high proportion of incident light at all angles
or dulldull:
reflecting only a low proportion of incident light, with no apparent sheen
, fleshyfleshy:
texture—fairly firm and dense, juicy or at least moist, and easily cut
or spongyspongy:
soft, light, discontinuous but cohesive, and somewhat resilient
.

Seed lanceolatelanceolate:
2D shape—lance-shaped; much longer than wide, with widest point below the middle, tapering to the apex (compare oblanceolate)
to teardrop-shapedteardrop-shaped:
2D shape—widest point is toward one end of the fruit, the other end tapers sharply to a pointed end
, tereteterete:
approximately circular in cross section; width and thickness approximately equal
in transectiontransection:
a cross section; representing a plane made by cutting across an organ at a right angle to its length
, 1–25 mm long. Seed coat brown, membranousmembranous:
texture—extremely thin, pliable, and fairly tough
, smooth, sometimes winged.

Embryo well developed, green, macropodousmacropodous:
an embryo having an enlarged or elongated hypocotyl
. Endospermendosperm:
nutritive starch- and oil-containing tissue present in many seeds
absent.

Identification features

Fruit
Type follicle, indehiscentindehiscent:
not opening on its own, as in a fruit
drupe
Size range 1.5–40 mm long
Shape(s) ovoid, ellipsoidellipsoid:
3D shape—elliptic
, oblong
Texture fleshy, spongy
Color(s) black, brown, green, yellow
Unique features Fleshy fleshy:
texture—fairly firm and dense, juicy or at least moist, and easily cut
or spongyspongy:
soft, light, discontinuous but cohesive, and somewhat resilient
, often beakedbeaked:
a usually firm, terminal appendage, sometimes tapered
, one-seeded folliclesfollicles:
a dry to (rarely) fleshy fruit derived from a single carpel that opens along a single longitudinal suture; the seeds may be arillate or with a fleshy testa
or indehiscentindehiscent:
not opening on its own, as in a fruit
drupesdrupes:
(indehiscent drupe) a fleshy, indehiscent fruit with one more hard pits enclosing seeds; (dehiscent drupe) a fruit with a dry or fibrous to fleshy or leathery outer husk that early to tardily breaks apart (or opens), exposing one or more nutlike pits enclosing the seeds
.
Seed
Size range 1–25 mm long
Shape(s) lanceoloid, oblongoblong:
2D shape—much longer than broad with nearly parallel sides, corners are rounded
, ellipsoidellipsoid:
3D shape—elliptic
, falcatefalcate:
shaped like a scythe or sickle
, teardrop-shaped
Surface relief smooth
Color(s) brown
Unique features Elongated seeds with very, thinthin:
having or being of relatively little depth
, brown seed coats and with macropodousmacropodous:
an embryo having an enlarged or elongated hypocotyl
, green embryos.
Other
Embryo well developed, green, macropodous
Nutritive tissuenutritive tissue:
tissue within the seeds that nourishes the developing embryo; such as endosperm, perisperm, or chalazosperm in angiosperms; megagametophyte in gymnosperms
endosperm endosperm:
nutritive starch- and oil-containing tissue present in many seeds
absent

Distribution

Mediterranean and temperate Australian coasts.

Distribution map courtesy of Angiosperm Phylogeny Website.

References

Baskin and Baskin 2021Baskin and Baskin 2021:
Baskin C and Baskin J. 2021. Relationship of the lateral embryo (in grasses) to other monocot embryos: A status up-grade. Seed Science Research 31 (3): 199-210. doi:10.1017/S0960258521000209
; Dahlgren et al. 1985Dahlgren et al. 1985:
Dahlgren RMT, Clifford HT, and Yeo PF. 1985. The families of the monocotyledons: structure, evolution, and taxonomy. Springer-Verlag, Berlin. 520 pp.
; Flora of Australia 2021+Flora of Australia 2021+:
Flora of Australia. Australian Biological Resources Study, Canberra. Accessed January-May 2021. URL: http://www.ausflora.org.au
; Guerrero-Meseguer et al. 2018Guerrero-Meseguer et al. 2018:
Guerrero-Meseguer L, Sanz-Laacute;zaro C, and Mariacute;n A. 2018. Understanding the sexual recruitment of one of the oldest and largest organisms on Earth, the seagrass Posidonia oceanica . PLoS ONE 13 (11): 1ndash;20. https://doi.org/10.1371/journal.pone.0207345
; Kirkbride et al. 2006Kirkbride et al. 2006:
Kirkbride JH, Jr, Gunn CR, and Dallwitz MJ. 2006. Family guide for fruits and seeds, vers. 1.0. Accessed September 2020ndash;January 2022. URL: https://nt.ars-grin.gov/seedsfruits/keys/frsdfam/index.cfm .
; Kubitzki et al. 1990+Kubitzki et al. 1990+:
Kubitzki K et al., eds. 1990+. The families and genera of vascular plants. 7+ vols. Berlin etc.
; Stevenson and Loconte 1995Stevenson and Loconte 1995:
Stevenson DW and Loconte H. 1995. A cladistic analysis of monocot families. In: Rudall PJ, Cribb PJ, Cutler DF, and Humphries CJ, eds. Monocotyledons: Systematics and Evolution. Royal Botanic Gardens, Kew.
; Thiele and Adams 2014Thiele and Adams 2014:
Thiele KR and Adams LG. 2014. Families of Flowering Plants of Australia. Accessed January-December 2021. URL: https://keys.lucidcentral.org/keys/v3/FFPA/key/FFPA/Media/Html/index.htm
; Watson and Dallwitz 1992+Watson and Dallwitz 1992+:
Watson L and Dallwitz MJ. 1992+. The families of flowering plants: descriptions, illustrations, identification, and information retrieval. Version: 6th Accessed September 2020-September 2022. URL: delta-intkey.com

*The number of genera and species is based on Christenhusz and Byng 2016Christenhusz and Byng 2016:
Christenhusz MJM and Byng JW. 2016. The number of known plant species in the world and its annual increase. Phytotaxa 261 (3): 201ndash;217. https://doi.org/10.11646/phytotaxa.261.3.1
, which may differ from the number of genera in GRIN-Global.

  Fruit:   Posidonia australis,  with calyx; Photo by R. Gibbons, USDA APHIS PPQ, Kirkbride et al. (2006)

Fruit: Posidonia australis, with calyx; Photo by R. Gibbons, USDA APHIS PPQ, Kirkbride et al. (2006)

  Fruit:   Posidonia australis ; Photo by R. Gibbons, USDA APHIS PPQ, Kirkbride et al. (2006)

Fruit: Posidonia australis; Photo by R. Gibbons, USDA APHIS PPQ, Kirkbride et al. (2006)

  Embryo:   Posidonia australis ; Illustration by K. Parker, Kirkbride et al. (2006)

Embryo: Posidonia australis; Illustration by K. Parker, Kirkbride et al. (2006)

  Fruits:   Posidonia australis ; Photo by D. Muirhead, gbif.org

Fruits: Posidonia australis; Photo by D. Muirhead, gbif.org

  Fruits, seed :  Posidonia australis , from left to right immature fruits, mature fruits, seed; Photo by A.J. Hunter, commons.wikimedia.org

Fruits, seed: Posidonia australis, from left to right immature fruits, mature fruits, seed; Photo by A.J. Hunter, commons.wikimedia.org