Family name: Asteraceae Berchtold & J. Presl or Compositae Giseke
Synonym(s): Acarnaceae Link, nom. illeg.; Ambrosiaceae Bercht. & J. Presl, nom. cons.; Anthemidaceae Bercht. & J. Presl; Aposeridaceae Raf.; Arctotidaceae Bercht. & J. Presl; Artemisiaceae Martinov; Athanasiaceae Martinov; Calendulaceae Bercht. & J. Presl; Carduaceae Bercht. & J. Presl; Cassiniaceae Sch. Bip., nom. inval.; Cichoriaceae Juss., nom. cons.; Compositae Giseke, nom. cons.; Coreopsidaceae Link, nom. inval.; Cynaraceae Spenn.; Echinopaceae Bercht. & J. Presl; Eupatoriaceae Bercht. & J. Presl; Helichrysaceae Link, nom. inval.; Inulaceae Bercht. & J. Presl; Lactucaceae Drude; Mutisiaceae Burnett; Partheniaceae Link, nom. inval.; Perdiciaceae Link, nom. inval.; Senecionaceae Bercht. & J. Presl; Vernoniaceae Burmeist.
Common name(s): aster family
*Number of genera/species: 1,683/24,700
List of genera records in GRIN-Global
Fruit indehiscent cypsela, rarely drupe (Chrysanthemoides, Wulffia), aggregated in a head (head rarely dispersal unit), sometimes heteromorphic for various traits within head. Fruit usually 2–5 mm long, range 0.2–70 mm long (includes beak, if present), globose to angled, sometimes curved, contorted, or coiled, terete, compressed, or flattened in transection, usually with distinctive apical rim or crown, which may be smooth, dentate, or crenulate, around persistent style base. Fruit sometimes beaked, if beaked often attenuate, winged or not, if winged, 1–3(–20) wings, wings lateral or encompassing, papery, membranous, or corky.
Cypsela 1-seeded, usually crowned by bristles, scales, or awns (=highly modified calyx called a pappus), pappus sometimes deciduous (falling as a unit) or absent. Cypsela rarely enclosed by persistent phyllary or receptacular bract, if present often hardened and forming bur (e.g. Acanthospermum, Ambrosia, Xanthium). Pappus usually white, yellow, or brown, sometimes purple, orange, or red, uniseriate or biseriate, and more than one form may be present on fruit. Abscission scar (or hilum) basal, lateral, or caudate, circular, usually surrounded by distinct tissue, differing in texture from scar or pericarp, termed carpopodium. Carpopodium an indistinct, narrow ring around scar to a tubular ring, up to 1/3 the length of the fruit body, or absent.
Pericarp usually black or brown, sometimes pale blue, green, gray, red, yellow, white, streaked, or mottled, rarely blue-black (drupelike fruit, Chrysanthemoides), often phytomelanin present contributing to black or darkly streaked color (Asteroideae, Heliantheae alliance), shiny or dull, often hardened, smooth or ribbed (3–40 ribs), ridged, grooved (rarely), pitted, reticulate, warty, wrinkled, papillose, spiculiferous (bearing spicules or needle-like protrusion), muricate, scaly, veined, or with hooks, bristles, spines, myxogenic cells, resin sacs or canals, and/or gland-dotted.
Fruit glabrous or pubescent, if pubescent, sparsely to densely so, with various types of hairs present, which may aid in identification (uniseriate barnadesioid, multicellular, one-celled, glandular, twin, rarely glochidiform). Pubescence or surface relief features may be restricted to apical or basal portions of fruit. Elaiosome (basal) or caruncle (apical) present in some genera, if present, white, smooth, or wrinkled.
Seed coat does not adhere to pericarp and traits may be helpful in identification within some tribes. More information is needed to include a comprehensive summary here.
Embryo well developed, completely to nearly completely filling seed coat, axile and centric, foliate, straight. Cotyledons spatulate. Endosperm present, scanty, smooth, oily.
Noxious Weeds: USA Federal Noxious Weed List, terrestrial, Ageratina adenophora (Sprengel) King & Robinson; Ageratina riparia (Regel) R.M. King and H. Robinson; Arctotheca calendula (Linnaeus) Levyns; Carthamus oxyacantha M. Bieberstein; Crupina vulgaris Cassini; Inula britannica Linnaeus; Mikania cordata (Burman f.) B. L. Robinson; Mikania micrantha Kunth; Onopordum acaulon Linnaeus; Onopordum illyricum Linnaeus; Senecio inaequidens DC.; Senecio madagascariensis Poir.; Tridax procumbens Linnaeus
Federal Noxious Weed Disseminules of the US ID tool provides keys, descriptions, and images of these species.
| Fruit | |
| Type | cypsela, drupe |
| Size range | usually 2–5 mm long, range 0.2–70 mm long |
| Shape(s) | globose, gibbous, lens-shaped, ellipsoid, linear, fusiform, falcate, ovoid, lanceoloid, urceoloid, conical, cylindrical, pyriform, cordiform, flask-shaped, wedge-shaped, 3- or 4-angled, sometimes curved, contorted, or coiled |
| Surface relief | smooth, ribbed (3–40 ribs), ridged, pitted, reticulate, warty, wrinkled, papillose, spiculiferous, muricate, scaly, veined, rarely grooved, or with hooks, bristles, spines, myxogenic cells, resin sacs or canals, gland-dotted |
| Color(s) | usually black or brown, sometimes pale blue, green, gray, red, yellow, white, streaked, or mottled, rarely blue-black |
| Unique features | Usually small, black or brown, hardened cypselae often topped with a cluster of bristles, scales or awns, which may be lost during handling, and style or stylar scar centered and conspicuous within the cluster. Abscission scars conspicuous at one end and opposite persistent styles or stylar scars. Seeds usually held within cypselae and completely or nearly completely filled with a straight embryo. |
| Other | |
| Embryo | well developed, completely to nearly completely filling seed coat, axile and centric, foliate, straight. Cotyledons spatulate. |
| Nutritive tissue | endosperm present, scanty, smooth, oily |
Distribution map courtesy of Angiosperm Phylogeny Website.
Flora of North America Editorial Committee 1993+; Frangiote-Pallone and de Souza. 2014; Kirkbride et al. 2006; Koekemoer et al. 2023; Kubitzki et al. 1990+; Lionakis Meyer 2017; Marzinek et al. 2008; Noxious Weed Regulations 2020; Takhtajan 2009; USDA 1980; Zhengyi et al. 2004+
*The number of genera and species is based on Christenhusz and Byng 2016, which may differ from the number of genera in GRIN-Global.
Authors: M. Islam, A. Miller, M. Maher, J. Scher, A. Redford
Content last updated November 2022
idtools.org
