Linaceae

Taxonomy

Family Name: Linaceae DC. ex Perleb

Synonym(s): Hugoniaceae Arn.

Common Name(s): flax family

*Number of genera/species: 10/255

List of genera records in GRIN-Global

Disseminule

fruit or seed, rarely fruit segment

Description

Fruit usually dehiscentdehiscent:
(v. dehisce) splitting open at maturity to release contents (of a fruit)
septicidal capsulecapsule:
a dry, dehiscent fruit formed by two or more carpels
, carpels (2, 3 or 5) only connate basally, each carpelcarpel:
a simple pistil that consists of a single ovary, style, and stigma
dehiscing into 2 one-seeded segments separated by false septaseptum:
(pl. septa) a dividing cross wall or partition
. Or sometimes dehiscentdehiscent:
(v. dehisce) splitting open at maturity to release contents (of a fruit)
drupe or rarely schizocarpschizocarp:
fruit formed from a single ovary, with fused carpels, with or without accessory tissue; splitting between locules to form distinct, indehiscent, usually one seeded segments; usually dry, rarely fleshy (compare mericarp)
breaking into 2 or 4 one-seeded nutletsnutlet:
˜achene
. Fruit 1–19 mm, globoseglobose:
3D shape—more or less spherical
to triangulartriangular:
2D shape—three relatively straight sides with distinct corners; more angular than teardrop-shaped
, 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
, 1–10 seeded, sometimes surrounded by persistent calyxcalyx:
the outer whorl of the perianth; all the sepals of a flower
. Pericarppericarp:
fruit wall or fruit coat
yellow, sometimes with purple-hued apexapex:
the point farthest from the point of attachment, or the "tip" of an organ
, or brown, smooth, glabrousglabrous:
without hairs
, sometimes pilosepilose:
having thin, soft, long hairs
. CapsulesCapsule:
a dry, dehiscent fruit formed by two or more carpels
thin- or thick-walled, fragile, membranousmembranous:
texture—extremely thin, pliable, and fairly tough
, or cartilaginouscartilaginous:
texture—firm, dense, tough, somewhat pliable, and resilient, like cartilage
. DrupesDrupe:
(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
fleshy, sometimes thinly fleshyfleshy:
texture—fairly firm and dense, juicy or at least moist, and easily cut
.

Seed compressedcompressed:
flattened; in grasses, used to denote compression (not necessarily flattened) either laterally or dorsiventrally
or flattened, lenticularlenticular:
3D shape—lens-shaped; biconvex
to reniformreniform:
2D or 3D shape—kidney-shaped
, triangulartriangular:
2D shape—three relatively straight sides with distinct corners; more angular than teardrop-shaped
or wedge-shapedwedge-shaped:
2D shape—triangular and tapering to a point at the base
, 0.4–6 mm. Sometimes arillate (Indorouchera, Philbornea) or with membranousmembranous:
texture—extremely thin, pliable, and fairly tough
wing (Reinwardtia, Tirpitzia). Seed black, brown, or reddish brown, 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
, coriaceouscoriaceous:
texture—leathery
, often mucilaginousmucilaginous:
resembling mucilage; moist and sticky
, smooth or reticulatereticulate:
surface relief—netted, raised walls or concave grooves forming a net-like surface pattern with flat, concave, or convex interspaces
, glabrousglabrous:
without hairs
.

Embryo well developed, completely to nearly filling seed cavity, axileaxile:
on or of the axis
and centric, foliatefoliate:
appearing leaf-like
, parallel to seed length, straight or slightly curvedcurved:
(of embryo) linear embryo is curved into an arch or horseshoe with the ends far apart
, with spatulatespatulate:
2D shape—like a spatula; rounded at the apex, with base long and tapered; (of embryo) embryo is straight and axile and centric with the cotyledons expanded to form the shape of a spatula or spoon; (of cotyledons) cotyledons expanded and wider than the stalk but not invested into the stalk
or investinginvesting:
(of embryo) embryo is nearly or completely filling seed coat, straight, and axile and centric with spatulate cotyledons and covering the stalk for at least half its length; (of cotyledons) cotyledons spatulate and covering the stalk for at least half its length
cotyledons.

Endosperm endosperm:
nutritive starch- and oil-containing tissue present in many seeds
usually scanty, sometimes copious, if present fleshy-soft.

Identification features

Fruit
Type	septicidal septicidal: 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 , 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 , schizocarp
Size range	1–19 mm long
Shape(s)	globose, ellipsoidellipsoid: 3D shape—elliptic , ovoidovoid: 3D shape—ovate , oblongoblong: 2D shape—much longer than broad with nearly parallel sides, corners are rounded , pyriform, triangular
Texture	capsules - fragile, membranousmembranous: texture—extremely thin, pliable, and fairly tough , cartilaginouscartilaginous: texture—firm, dense, tough, somewhat pliable, and resilient, like cartilage , thick-walled drupes - fleshy
Surface relief	smooth
Color(s)	yellow, sometimes with purple hues on upper portion, brown
Unique features	Usually yellow or brown septicidalsepticidal: type of capsular dehiscence, opening longitudinally by separating between the septa of adjacent carpels capsulescapsule: a dry, dehiscent fruit formed by two or more carpels splitting into 4–10, 1-seeded, segments, remaining basally connate. Sometimes yellow or brown fleshyfleshy: texture—fairly firm and dense, juicy or at least moist, and easily cut drupesdrupe: (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 with up to 10 seeds, sometimes splitting into indehiscentindehiscent: not opening on its own, as in a fruit mericarps. Fruits often with mucilaginousmucilaginous: resembling mucilage; moist and sticky seeds.
Seed
Size range	0.4–6 mm long
Shape(s)	lenticular, ellipsoidellipsoid: 3D shape—elliptic , ovoidovoid: 3D shape—ovate , oblongoblong: 2D shape—much longer than broad with nearly parallel sides, corners are rounded , reniform
Surface relief	smooth, reticulate
Color(s)	black, brown, reddish brown
Unique features	Small dark seeds, compressedcompressed: flattened; in grasses, used to denote compression (not necessarily flattened) either laterally or dorsiventrally or flattened, usually smooth and often mucilaginousmucilaginous: resembling mucilage; moist and sticky .
Other
Embryo	well developed, completely to nearly filling seed cavity, axileaxile: on or of the axis and centric, foliatefoliate: appearing leaf-like , parallel to seed length, straight or slightly curvedcurved: (of embryo) linear embryo is curved into an arch or horseshoe with the ends far apart , with spatulatespatulate: 2D shape—like a spatula; rounded at the apex, with base long and tapered; (of embryo) embryo is straight and axile and centric with the cotyledons expanded to form the shape of a spatula or spoon; (of cotyledons) cotyledons expanded and wider than the stalk but not invested into the stalk or investinginvesting: (of embryo) embryo is nearly or completely filling seed coat, straight, and axile and centric with spatulate cotyledons and covering the stalk for at least half its length; (of cotyledons) cotyledons spatulate and covering the stalk for at least half its length cotyledons
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 usually scanty, sometimes copious, if present fleshy-soft

Distribution

Worldwide

Distribution map courtesy of Angiosperm Phylogeny Website.

References

Flora of North America Editorial Committee, eds. 1993+; González-Velasco et al. 2022González-Velasco et al. 2022:
González-Velasco J, Burgos M, Galván-Escobedo I and Castillo-Campos G. 2022. Taxonomic update of the flax family in Mexico. Phytotaxa 549: 141–184. https://doi.org/10.11646/phytotaxa.549.2.3; 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 .; 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.; Takhtajan 2009Takhtajan 2009:
Takhtajan A. 2009. Flowering plants: Second edition. Springer Nature, Switzerland. 871 pp.; 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 & Missouri Botanical Garden, St. Louis USA. Accessed January–March 2024. 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): 201-217. https://doi.org/10.11646/phytotaxa.261.3.1, which may differ from the number of genera in GRIN-Global.