Casuarinaceae

Disclaimer

Content is from Kirkbride et al. 2006, without modification. 
Updates are forthcoming.

Taxonomy

Casuarinaceae R. Brown

Common name: She-oak Family.

Number of genera: 4 genera.

Number of species (Mabberley 1997): 70 species.

Disseminule

Fruit (intact or entire) (fruiting head).

Description

Fruits: Pistil(s) 1; 1-pistillate. Fruit anthocarp, or pericarpium; simple; samara (individual fruits are samaras, but they are within a conelike structure named trymconum); compound, or multiple; trymoconum (Allocasuarina fraseriana (Miq.) L. A. S. Johnson, Spjut Fig. 53A & 2 families Casuarinaceae, Cyclanthaceae); without persistent central column; within accessory organ(s); imbricately arranged with conelike structure & within woody bracteoles; 1-seeded; 1-seeded; with 1-carpellate; apex not beaked; indehiscent. Epicarp brown (all shades), or black, or gray, or yellow; shiny, or dull; durable; without armature; with wing(s); 1-winged; with wing(s) apical; without apical respiratory hole. Mesocarp absent. Endocarp present; not separating from exocarp; thin; not splitting into 1-seeded pyrenes; smooth; without wing; without operculum; without secretory cavities; without mechanism for seedling escape; without grooves; without longitudinal ridges. Funiculus short; short without seed bearing hooks (retinacula); not persisting in fruit after seed shed.

Seeds: Aril absent. Seed minute; not bowl shaped; not nutlike; without winglike beak; without caudate appendage(s); at maturity without food reserves, or with food reserves; with endosperm; without canavanine. Sarcotesta absent. Testa present, or absent; adnate to epicarp; without embryo surrounded and capped by viscid tissue; without fleshy or leathery layer over hard layer; tight; surface smooth; without crease or line separating cotyledons from hypocotyl-radicle; without notch along margin where cotyledons from hypocotyl-radicle tip approach each other; without glands; without bristles; glabrous; without wings; without collar; without operculum; transparent; monochrome; thin, or membranous; not becoming mucilaginous when wetted; surrounding embryo. Endosperm development nuclear. Embryo differentiated from food reserve; well developed; 1 per seed; completely filling testa (no food reserve); at one end of seed not extending into a depression or cup; straight; parallel to seed length; with cotyledons abruptly connected to hypocotyl-radicle (nearly); without coleorhiza; without simmondsin; with cotyledons containing oils; without stomata; not green; with 2 or more cotyledons. Cotyledons 2; well developed; 0.28 times length of embryo; 2–3 times wider than hypocotyl-radicle; not concealing hypocotyl-radicle; thick; flat; smooth; with apices entire; with margins separate; basally entire; equal in size; not punctate dotted. Hypocotyl-radicle moderately developed (at best); straight; not thickened.

Habitat and crop association

Noxious weeds: 1 or more USA state noxious weeds in this family.

USA states and territories with listed noxious weeds: Florida (FL).

USA state and territory noxious weeds:

Casuarina spp.: USA state noxious weed: FLª.

Symbols: ªaquatic weed; ●terrestrial weed; °weed in seed.

Last updated February 2006.

Distribution

General distribution: Old World.

Detailed distribution: Asia Southeastern to Oceania (mainly Australia).

Notes

Samara is seedlike in appearance and enclosed in woody bracteole which separate at maturity. Woody head of bracteoles resembles miniature pine cones.

References

Literature specific to this family: Johnson, L.A.S. & K.L. Wilson. 1989. Casurarinaceae: A synopsis. In: P.R. Crane & S. Blackmore, eds., Evolution, Systematics, and Fossil History of the Hamamelidae. Vol 2: 'Higher' Hamamelidae. Systematics Association Special Volume No. 40B, pp. 167–188. Clarendon Press, Oxford.

General references: Corner, E.J.H. 1976. The seeds of Dicots, esp. vol. 2. Cambridge University Press, New York, Cronquist, A. 1981. An integrated system of classification of flowering plants, 1,262 p. Columbia University Press, New York, Goldberg, A. 1986 (dicots) & 1989 (monocots). Classification, evolution, and phylogeny of the familes of Dicotyledons. Smithsonian Contr. Bot. 58 for dicots (314 pp.) & 71 for monocots (74 pp.). [Goldberg's illustrations are reproduced from older publications and these should be consulted], Gunn, C.R., J.H. Wiersema, C.A. Ritchie, & J.H. Kirkbride, Jr. 1992 & amendments. Families and genera of Spermatophytes recognized by the Agricultural Research Service. Techn. Bull. U.S.D.A. 1796:1–500, Schopmeyer, C.S. 1974. Seeds of Woody plants in the United States. Agric. Handb. 450:1–883, Spjut, R.W. 1994. A systematic treatment of fruit types. Mem. New York Bot. Gard. 70:1–182, and Wood, C.E., Jr. 1974. A student's atlas of flowering plants: Some dicotyledons of eastern North America, 120 pp. Harper & Row, New York.