Stemonaceae

Taxonomy

Family name: Stemonaceae Caruel

Synonym(s): Croomiaceae Nakai; Pentastemonaceae Duyfjes; Roxburghiaceae Wall.

Common name(s): stemona family

*Number of genera/species: 4/37

List of genera records in GRIN-Global

Disseminule

seed(s); fruit (indehiscent)

Description

Fruit dehiscentdehiscent:
(v. dehisce) splitting open at maturity to release contents (of a fruit)
, septicidalsepticidal:
type of capsular dehiscence, opening longitudinally by separating between the septa of adjacent carpels
capsulecapsule:
a dry, dehiscent fruit formed by two or more carpels
(2-valved), or indehiscentindehiscent:
not opening on its own, as in a fruit
, berryberry:
an indehiscent, fleshy fruit with one or a few to many seeds. The flesh may be homogenous throughout. Or, if the outer part is hard, firm, or leathery, referred to as an hesperidium. Septa are present in some, and the seeds may be arillate or with a fleshy testa.
(Pentastemona), 7–70 mm long, globoseglobose:
3D shape—more or less spherical
, ovoidovoid:
3D shape—ovate
, or oblongoblong:
2D shape—much longer than broad with nearly parallel sides, corners are rounded
, roundround:
2D shape—orbiculate; circular
or compressedcompressed:
flattened; in grasses, used to denote compression (not necessarily flattened) either laterally or dorsiventrally
in transectiontransection:
a cross section; representing a plane made by cutting across an organ at a right angle to its length
, sometimes beakedbeaked:
a usually firm, terminal appendage, sometimes tapered
or with wings, one seeded to many seeded. Pericarppericarp:
fruit wall or fruit coat
green, membranousmembranous:
texture—extremely thin, pliable, and fairly tough
, sharply ridgedridged:
surface relief—raised, thick ridges, sharp edged or rounded, usually in a series that may cover the entire surface
in Pentastemona (10 laterallateral:
(of embryo) embryo lies along the side of the seed, generally towards one end; of, at, or from the side; in grasses, can refer to the sides adjacent to the dorsal and ventral sides
ridges or ribs). One to few seeds apically attached in Croomia and Stichoneuron. One to ten seeds basally attached in Stemona and with long funicles. Funicles short in all other genera.

Seed globoseglobose:
3D shape—more or less spherical
to mitaformmitaform:
shaped like a child's mitten
, 1–20 mm long, 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
, elaiosomeelaiosome:
a lipid and protein-rich fleshy structure attached to some seeds and fruits, it attracts ants which then disperse the disseminule (e.g., caruncle in the Euphorbiaceae, the aril (outgrowth of the funiculus) in the Fabaceae)
present and variable on or near funicle. Seed coat shinyshiny:
uniformly reflecting a high proportion of incident light at all angles
, leatheryleathery:
texture—moderately thick, tough, and very pliable
, thickthick:
having or being of relatively great depth
or thinthin:
having or being of relatively little depth
, reticulatereticulate:
surface relief—netted, raised walls or concave grooves forming a net-like surface pattern with flat, concave, or convex interspaces
, ribbedribbed:
surface relief—wide, prominent, linear ridges that are generally rounded and longitudinally situated on the surface
, ridgedridged:
surface relief—raised, thick ridges, sharp edged or rounded, usually in a series that may cover the entire surface
, or groovedgrooved:
surface relief—linear depressions that may be single or form a series of grooves over the surface
. In Pentastemona, a collarlike elaiosomeelaiosome:
a lipid and protein-rich fleshy structure attached to some seeds and fruits, it attracts ants which then disperse the disseminule (e.g., caruncle in the Euphorbiaceae, the aril (outgrowth of the funiculus) in the Fabaceae)
covers about 1/3 of the seed and a transparent sarcotestasarcotesta:
pulpy or fleshy outer layer of the seed coat, simulates aril
is also present, which is visible even in drydry:
texture—free or relatively free from water or liquid
seeds. The elaiosomeselaiosomes:
a lipid and protein-rich fleshy structure attached to some seeds and fruits, it attracts ants which then disperse the disseminule (e.g., caruncle in the Euphorbiaceae, the aril (outgrowth of the funiculus) in the Fabaceae)
in Croomia and Stichoneuron are composed of uniseriate hairs, which are flimsy in Stichonueron. In Stemona, elaiosomeselaiosomes:
a lipid and protein-rich fleshy structure attached to some seeds and fruits, it attracts ants which then disperse the disseminule (e.g., caruncle in the Euphorbiaceae, the aril (outgrowth of the funiculus) in the Fabaceae)
are lobed and of vesicular hairs.

Embryo small, well developed, linearlinear:
(shape) long, narrow, and uniform in width; (of embryo) embryo is straight and much longer than wide
, straight or minute, rudimentaryrudimentary:
(of embryo) embryo is small and fills less than a quarter of the seed and can be variable in shapes, such as linear, spatulate, or oval
(Pentastemona). Endospermendosperm:
nutritive starch- and oil-containing tissue present in many seeds
copious, fleshyfleshy:
texture—fairly firm and dense, juicy or at least moist, and easily cut
or hard, smooth.

Identification features

Fruit
Type	capsule, berry
Size range	7–70 mm long
Shape(s)	globose, ovoidovoid: 3D shape—ovate , or oblong
Texture	membranousmembranous: texture—extremely thin, pliable, and fairly tough
Surface relief	sharply ridgedridged: surface relief—raised, thick ridges, sharp edged or rounded, usually in a series that may cover the entire surface in one genus
Color(s)	green
Unique features	Green capsulescapsules: a dry, dehiscent fruit formed by two or more carpels or berriesberries: an indehiscent, fleshy fruit with one or a few to many seeds. The flesh may be homogenous throughout. Or, if the outer part is hard, firm, or leathery, referred to as an hesperidium. Septa are present in some, and the seeds may be arillate or with a fleshy testa. bearing ornamented seeds with elaiosomeselaiosomes: a lipid and protein-rich fleshy structure attached to some seeds and fruits, it attracts ants which then disperse the disseminule (e.g., caruncle in the Euphorbiaceae, the aril (outgrowth of the funiculus) in the Fabaceae) .
Seed
Size range	1–20 mm long
Shape(s)	mitaform, oblongoblong: 2D shape—much longer than broad with nearly parallel sides, corners are rounded , ovoidovoid: 3D shape—ovate , ellipsoidellipsoid: 3D shape—elliptic , globose
Surface relief	reticulate, ribbedribbed: surface relief—wide, prominent, linear ridges that are generally rounded and longitudinally situated on the surface , ridgedridged: surface relief—raised, thick ridges, sharp edged or rounded, usually in a series that may cover the entire surface , grooved
Unique features	Shiny, ornamented seeds with leatheryleathery: texture—moderately thick, tough, and very pliable seed coats and elaiosomeselaiosomes: a lipid and protein-rich fleshy structure attached to some seeds and fruits, it attracts ants which then disperse the disseminule (e.g., caruncle in the Euphorbiaceae, the aril (outgrowth of the funiculus) in the Fabaceae) .
Other
Embryo	small, well developed, linearlinear: (shape) long, narrow, and uniform in width; (of embryo) embryo is straight and much longer than wide , straight or minute, rudimentaryrudimentary: (of embryo) embryo is small and fills less than a quarter of the seed and can be variable in shapes, such as linear, spatulate, or oval (Pentastemona)
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 copious, fleshyfleshy: texture—fairly firm and dense, juicy or at least moist, and easily cut or hard, smooth

Distribution

India, southern China, Japan to Australia, and southeast USA.

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; Flora of North America Editorial Committee 1993+Flora of North America Editorial Committee 1993+:
Flora of North America Editorial Committee, eds. 1993+. Flora of North America North of Mexico [Online]. 22+ vols. Flora of North America Association, New York and Oxford. Accessed January-December 2021. URL: http://beta.floranorthamerica.org.; 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.; Nooteboom et al. 2021; Zhengyi et al. 2004+Zhengyi et al. 2004+:
Zhengyi W, Raven PH, and Deyuan H. 2004+. Flora of China [online]. 25 vols. Science Press, Beijing China amp; Missouri Botanical Garden, St. Louis USA. Accessed January-December 2021. http://flora.huh.harvard.edu/china/

*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.