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Synonyms: Avetraceae Takht.; Stenomeridaceae J. Agardh, nom. cons.; Taccaceae Dumort., nom. cons.; Tamaceae Bercht. & J. Presl; Trichopodaceae Hutch.
Common name: Yam Family.
Number of genera 9. Number of species 640.
Angiosperm. Liliopsida.
Disseminule a dehisced fruit, or an intact or entire fruit, or a seed.
Fruits
Pistil(s) compound; 1; 1-pistillate; with carpels united. Fruit pericarpium; simple; capsule, or berry (Tamus, Avetra), or samara (samaroid Rajania & Trichopus but not Spjut); denticidal capsule, or loculicidal capsule (of authors); capsule not inflated; capsule without operculum; berry indehiscent; berry without central placental mass; without persistent central column; not within accessory organ(s), or within accessory organ(s); within calyx (Tacca); 1-seeded to many-seeded; 1-seeded (many in Stenomeris); less than 1 cm long to from 1–5 cm long; 1–5 cm long; 3-carpellate; with carpels united; with carpels remaining united at maturity; with carpels not radiating at maturity; without sterile carpels; in transection angled, or terete; 3-angled; apex not beaked; wall membranaceous, or fleshy; dehiscent, or indehiscent. Dehiscent unit seed(s). Dehiscent regularly, or irregularly (Trichopus opens irregularly by fruit wall rupturing); passively; linearly; by dorsal sutures and ventral sutures; at apex; and shedding seeds; without replum. Epicarp brown (all shades), or black, or green, or orange, or purple, or red, or yellow; shiny, or dull; durable; not glabrous (with hairs); hairs not glandular; without armature; smooth, or not smooth; Tacca 6 ridged; with wing(s), or without wing(s); 3-winged; with wing(s) lateral; without apical respiratory hole. Mesocarp absent, or present; fleshy; composed of 1 unified layer; without lactiform cavity system. Endocarp present, or absent; 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 larger than minute; 1 to less than 5 mm long to 5 to less than 10 mm long; 2–8 mm long; circular, or irregular, or obovate, or curved, or straight, or oblong, or elliptic, or ovate, or reniform, or angular, or C-shaped; in transection flattened, or terete; not bowl shaped; not nutlike; without winglike beak; without caudate appendage(s), or with caudate appendage(s) (Tacca); at maturity with food reserves; with endosperm; without canavanine. Sarcotesta absent. Testa present; with markedly different marginal tissue, or without markedly different marginal tissue; marginal tissue winglike; without fleshy or leathery layer over hard layer; tight; dull; surface unsmooth; surface with depressed features, or discreet raised features, or merged raised features; surface 1- grooved; surface papillate; surface wrinkled, or reticulate, or ridged, or striate, or ribbed (15–19 longitudinally); 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, or pubescent; with hairs over surface; with short hairs; densely hairy; tomentose; without agglutinated hairs; without mucilaginous hairs; without glandular pubescence; with wing(s), or without wings; 1-winged; with wing encompassing seed, or wing at one end; with solid wing(s) similar to testa; without collar; without operculum; colored; monochrome; brown (all shades); coriaceous; not becoming mucilaginous when wetted; surrounding food reserve. Raphe conspicuous, or inconspicuous; fleshy; as long as seed; included in dehisced fruit. Endosperm development nuclear, or cellular (latter becoming); copious; hard (or horny), or cartilaginous, or fleshy; transparent; smooth, or ruminate (Trichopus), or pitted (Epipetrum); without starch, or with starch (nearly without); with proteins, oils, and hemicellulose; without fatty acid containing cyclopropene; without apical lobes; without chlorophyll; without isodiametric faceted surface; without odor.
Embryo differentiated from food reserve; well developed; 1 per seed; partially filling testa (with food reserve); chamber basal to wing, or central to wings; 0.1–0.3 times the length of food reserve; at one end of seed not extending into a depression or cup; basal; linear, or miniature; capitate; linear; straight; oblique to seed length, or parallel to seed length; with cotyledons gradually connected to hypocotyl-radicle; without coleoptile; without coleorhiza; without simmondsin; without stomata; not green; with 1 cotyledon (sometime with 2nd vestigal cotyledon). Cotyledons one and lateral with terminal plumule; not modified into scutellum; not circinately coiled. Hypocotyl-radicle small; straight; not thickened. Plumule minute; composed of 1 seed-leaf; straight; lateral and not fitting into groove along terminal cotyledon.
Distribution
Cosmopolitan. New World, Old World. North America, Middle America, South America, Europe, Africa, Asia Major, Asia Minor, southeastern Asia, Australia, Oceania.
Notes
For Tacca: Drenth (1972) clearly stated that this fruit does not dehisce, thus Spjut's "loculicidal capsule" is wrong. Likely, Spjut copied Cronquist & Goldberg.
Weed information
1 or more USA state noxious weeds.
USA states and territories with listed noxious weeds: Alabama (AL), Florida (FL).
USA state and territory noxious weeds: -- Dioscorea alata L.: USA state noxious weed: FL●. -- Dioscorea bulbifera L.: USA state noxious weed: AL●, FL●. -- Symbols: ªaquatic weed; ●terrestrial weed; °weed in seed. -- Last updated September 2008.
Listed seeds
ISTA listed seeds.
ISTA listed seeds: -- Dioscorea alata L.w -- Dioscorea bulbifera L. w -- Dioscorea cayenensis Lam. -- Dioscorea esculenta (Lour.) Burkill -- Dioscorea hispida Dennst. -- Dioscorea trifida L. f. -- Symbols: aagricultural and vegetable seeds (Table 2A Part 1); ttree and shrub species (Table 2A Part 2); fflower, spice, herb, and medicinal seeds (Table 2A Part 3); wweed seeds. -- Last updated September 2008.
Accepted genera
Dioscorea L., nom. cons. prop. -- Stenomeris Planch. -- Tacca J. R. Forst. & G. Forst., nom. cons. -- Trichopus Gaertn.
References specific to this family
Cronquist page 1228 (including Taccaceae, 1223).
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, Dahlgren, R.M.T., H.T. Clifford and P.F. Yeo. 1985. The families of the monocotyledons, 520 pp. Springer-Verlag, Berlin, Gaertner, J. 1788–1805. De fructibus et seminibus plantarum. The Author, Stuttgart, Goldberg, A. 1986 (dicots) and 1989 (monocots). Classification, evolution, and phylogeny of the familes of Dicotyledons. Smithsonian Contr. Bot. 58 for dicots (314 pp.) and 71 for monocots (74 pp.). [Goldberg's illustrations are reproduced from older publications and these should be consulted], Gunn, C.R. and C.A. Ritchie. 1988. Identification of disseminules 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, and J.H. Kirkbride, Jr. 1992 and amendments. Families and genera of Spermatophytes recognized by the Agricultural Research Service. Techn. Bull. U.S.D.A. 1796:1–500, LeMaout, E. and J. Decaisne. 1876. A general system of botany, 1,065 p. Longmans, Green, and Co., London, Mabberley, D.J. 1987. The plant-book, 706 p. Cambridge University Press, Cambridge, Martin, A.C. 1946. The comparative internal morphology of seeds. Amer. Midl. Naturalist 36:513–660, Spjut, R.W. 1994. A systematic treatment of fruit types. Mem. New York Bot. Gard. 70:1–182.
Illustrations
Acceptable fruit and seed illustrations. Disseminule illustration(s): fruit, or seed, or embryo. Fruit illustration(s): LeMaout & Decaisne, Cronquist, Dahlgren et al. Seed illustration(s): Cronquist, LeMaout & Decaisne, Dahlgren et al., Karen, Gunn & Ritchie. Embryo illustration(s): Dahlgren et al., Karen, Gunn & Ritchie, Martin. Karen's plate number and taxon (taxa): 380: Dioscorea glauca Rusby (A-B), Epipetrum bilobum (C-D), Dioscorea (Nanarepenta) tolucana (Matuda) Caddiick & Wilkin (E-F), Rajania hastata LO. (G-H), Stenomeris discoreafolia Planch. (I-J), Tamus communis L. (K-L), Trichopus zelanicus Gaertn. (M-N).
• Fruit. 1 of 7. Dioscorea sinuata Vell.: fruit. • Seed. 2 of 7. Dioscorea sinuata Vell.: seeds. • Seed. 3 of 7. Tacca leontopetaloides (L.) Kuntze: seeds. • Embryo. 4 of 7. Epipetrum bilobum Phil.: embryo. • Embryo. 5 of 7. Rajania hastata L.: embryo. • Embryo. 6 of 7. Stenomeris dioscoreifolia Planch.: embryo. • Embryo. 7 of 7. Tacca leontopetaloides (L.) Kuntze: embryo.
We advise against extracting comparative information from the descriptions. This is much more easily achieved using the DELTA data files or the interactive key, which allows access to the character list, illustrations, full and partial descriptions, diagnostic descriptions, differences and similarities between taxa, lists of taxa exhibiting or lacking specified attributes, and distributions of character states within any set of taxa. See also Guidelines for using data taken from Web publications.
Cite this publication as: ‘J.H. Kirkbride, Jr., C.R. Gunn, and M.J. Dallwitz. 2000 onwards. Family guide for fruits and seeds: descriptions, illustrations, identification, and information retrieval. Version: 12th April 2021. delta-intkey.com’.
