Elatinaceae

Disclaimer

Content is from 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 2020-January 2022. URL:  https://nt.ars-grin.gov/seedsfruits/keys/frsdfam/index.cfm ., without modification. 
Updates are forthcoming.

Taxonomy

Elatinaceae Dumortier

Common name: Waterwort Family.

Number of genera: 2 genera.

Number of species (Mabberley 1997): 32 species.

Disseminule

Fruit (dehisced), or seed.

Description

Fruits: Pistil(s) compound; 1; 1-pistillate; with carpels united. Fruit pericarpium; simple; capsulecapsule:
a dry, dehiscent fruit derived from a compound ovary
; septicidalsepticidal:
type of capsular dehiscence, opening longitudinally by separating between the septa of adjacent carpels
capsulecapsule:
a dry, dehiscent fruit derived from a compound ovary
(Bergia ammannioides Roxb. & Elatine hydropiper L.), or septifragalseptifragal:
type of capsular dehiscence, splitting through the exterior wall suture(s) but not the septum(-a), the valves of the wall then separating from the septum(-a) and the locules thus opened directly to the outside
capsulecapsule:
a dry, dehiscent fruit derived from a compound ovary
(other authors, but not Spjut); capsulecapsule:
a dry, dehiscent fruit derived from a compound ovary
not inflated; capsulecapsule:
a dry, dehiscent fruit derived from a compound ovary
without operculumoperculum:
a dehiscent cap (or lid) of a seed or fruit that opens during germination or dehiscence
; with persistent central column; not within accessory organ(s); many-seeded; many; less than 1 cm long (assumed); with 2–5-carpellate; with carpels united; with carpels remaining united at maturity; with carpels not radiating at maturity; without sterilesterile:
lacking male and/or female reproductive parts; also, not producing fruit or seed
carpels; apexapex:
the point farthest from the point of attachment, or the "tip" of an organ
not beaked; dehiscentdehiscent:
(v. dehisce) splitting open at maturity to release contents (of a fruit)
. Dehiscentdehiscent:
(v. dehisce) splitting open at maturity to release contents (of a fruit)
unit seed(s). Dehiscentdehiscent:
(v. dehisce) splitting open at maturity to release contents (of a fruit)
at apexapex:
the point farthest from the point of attachment, or the "tip" of an organ
; and shedding seeds; without replumreplum:
the rim, formed by the persistent placentas, and connected by a false septum in Brassicaceae fruits. The fruit valves are attached to this rim and separate from it in dehiscent fruits.
. Epicarpepicarp:
outer layer of fruit wall or pericarp, if divided into layers; note here used synonymously with exocarp
durable; glabrousglabrous:
without hairs
; without armature; without wing(s); without apicalapical:
at or pertaining to the end of the seed or fruit distal from its point of attachment (i.e., base)
respiratory hole. Mesocarpmesocarp:
the middle layer of the pericarp, if divided into layers
absent. Endocarpendocarp:
the inner layer of the pericarp, if divided into layers
present; not separating from exocarpexocarp:
outer layer of fruit wall or pericarp, if divided into layers; note here used synonymously with epicarp
; thin; not splitting into 1-seeded pyrenes; smooth; without wing; without operculumoperculum:
a dehiscent cap (or lid) of a seed or fruit that opens during germination or dehiscence
; without secretory cavities; without mechanism for seedling escape; without grooves; without longitudinallongitudinal:
of or relating to length or the lengthwise dimension
ridges. Funiculusfuniculus:
(alt. funicle) stalk connecting the ovule (later seed) to the ovary (later fruit) placenta
short; short without seed bearing hookswith hooks:
bristles or spines with curved or backwards pointing tips, or with secondary bristles along their length
(retinacula); not persisting in fruit after seed shed.

Seeds: Arilaril:
(broad sense) appendicular structure that wholly or partly envelops a seed and is produced from or a modification of the funicle, raphe, or outer integument; usually fleshy or pulpy, sometimes spongy or tufted-capillate, often brightly colored
absent. Seed minute; straight, or C-shapedC-shaped:
2D-shape—semiannulate, curved into the shape of the letter 'C'
, or U-shaped; in transection tereteterete:
approximately circular in cross section; width and thickness approximately equal
; not bowl shaped; not nutlike; without winglike beakbeak:
a usually firm, terminal appendage, sometimes tapered
; without caudatecaudate:
tapering to a long, tail-like appendage
appendage(s); at maturity with food reserves, or without food reserves; with endosperm; without canavanine. Sarcotestasarcotesta:
pulpy or fleshy outer layer of the seed coat, simulates aril
absent. Testatesta:
seed coat
present; without markedly different marginalmarginal:
at, on, or close to the margin or border
tissue; without fleshy or leatheryleathery:
texture—moderately thick, tough, and very pliable
layer over hard layer; tight; surface unsmooth, or smooth (Merimea); surface with merged raised features; surface reticulatereticulate:
surface relief—netted, raised walls or concave grooves forming a net-like surface pattern with flat, concave, or convex interspaces
, or striatestriate:
surface relief—having fine, parallel lines, grooves or ridges
(transversely), or sculptured; 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; glabrousglabrous:
without hairs
; without wings; without collar; without operculumoperculum:
a dehiscent cap (or lid) of a seed or fruit that opens during germination or dehiscence
; colored; monochrome; thin; not becoming mucilaginousmucilaginous:
resembling mucilage; moist and sticky
when wetted; surrounding embryo, or surrounding food reserve. Hilumhilum:
on seeds, the scar indicating where the funiculus was attached; on grass caryopses, the scar visible on the outer fruit surface revealing where the seed is attached on the inner fruit wall surface; or in Asteraceae cypselae, the scar visible on the outer fruit wall revealing where the fruit was attached to the receptacle
basalbasal:
at or pertaining to the point of attachment; (of embryo) embryo occupies one end of the seed
. Endosperm development nuclear; scant. Embryo differentiated from food reserve; well developed; 1 per seed; completely filling testatesta:
seed coat
(no food reserve), or nearly filling testatesta:
seed coat
(trace or scanty food reserve); 1 times the length of food reserve (nearly); at one end of seed not extending into a depression or cup; axileaxile:
on or of the axis
and centric; linearlinear:
(shape) long, narrow, and uniform in width; (of embryo) embryo is straight and much longer than wide
; straight, or arcuate, or U-shaped; parallel to seed length; with cotyledons gradually connected to hypocotyl-radicle; without coleorhiza; without simmondsin; without stomata; not green; with 2 or more cotyledons. Cotyledons 2; tiny, or moderately developed; 0.2–0.6 times length of embryo; as wide as hypocotyl-radicle; 1 times wider than hypocotyl-radicle; not concealing hypocotyl-radicle; not foliaceous; moderately thick; flat; smooth; with apicesapex:
the point farthest from the point of attachment, or the "tip" of an organ
entire; with margins separate; basally entire; equal in size; not punctatepunctate:
surface relief—dotted with pits or with translucent, sunken glands or with colored dots, similar to pitted
dotted. Hypocotyl-radicle well developed; straight; not thickened.

Distribution

General distribution: Cosmopolitan (except for Arctic). New World and Old World.

Detailed distribution: North America to Oceania.

Notes

Mabberley & Cronquist have only septifragalseptifragal:
type of capsular dehiscence, splitting through the exterior wall suture(s) but not the septum(-a), the valves of the wall then separating from the septum(-a) and the locules thus opened directly to the outside
capsulecapsule:
a dry, dehiscent fruit derived from a compound ovary
, but Goldberg has occasionally leaving a columnella.

References

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, Engler, A. & K. Prantl. 1924 and onward. Die Natürlichen Pflanzenfamilimien. W. Engelman, Leipzig, Gaertner, J. 1788–1805. De fructibus et seminibus plantarum. The Author, Stuttgart, 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], Gray, A. 1848. Genera florae Americae boreali-orientalis illustrata, 2 vols. James Munroe & Co., Boston., Gunn, C.R. & C.A. Ritchie. 1988. Identification of disseminulesdisseminule:
detachable plant part capable of being disseminated and of propagating, commonly a seed or fruit
listed in the Federal Noxious Weed Act. Techn. Bull. U.S.D.A. 1719:1–313, 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, LeMaout, E. & J. Decaisne. 1876. A general system of botany, 1,065 p. Longmans, Green, & Co., London, Mabberley, D.J. 1987. The plant-book, 706 p. Cambridge University Press, Cambridge, and Spjut, R.W. 1994. A systematic treatment of fruit types. Mem. New York Bot. Gard. 70:1–182.