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Key to families | Table of families and genera
Indexes to all accepted names and synonyms:
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Annual to tree. Leaf: basal and/or cauline, alternate, opposite, rarely whorled, simple to 2+ × compound. Inflorescence: 1° inflorescence a head, resembling a flower, of several types (see below), 1–many in generally ± cyme-like cluster; each head generally with ± calyx-like involucre of 1–many series of phyllaries (involucral bracts); receptacle of head flat to conic or columnar, paleate (bearing paleae = receptacle bracts) or epaleate; flowers 1–many per head. Flower: bisexual, unisexual, or sterile, ± small, of several types (see below); calyx 0 or modified into ± persistent pappus of bristles, scales, and/or awns; corolla radial or bilateral (0), lobes generally (0)3–5; stamens 4–5, filaments generally free, generally fused to corolla at tube/throat junction, anthers generally fused into cylinder around style, anther base generally rounded or cordate (deeply sagittate or with tail-like appendages), tip (= flattened appendage) generally projecting beyond pollen sac; pistil 1, 2-carpeled, ovary inferior, 1-chambered, 1-seeded, placenta basal, style 1, tip generally ± 2-branched (except in some staminate disk flowers), branch tips truncate or generally bearing ± brush-like appendages; stigmas 2, generally on adaxial faces of style branches. Fruit: achene (also called a cypsela) (drupe in Chrysanthemoides), cylindric to ovoid, sometimes compressed, generally deciduous with pappus attached.
± 1500 genera, 23000 species: worldwide, many habitats. Flower and head types differ in form and sexual condition. A disk flower has a generally radial corolla, with a cylindric tube, expanded throat, and generally 5 lobes. Disk flowers are generally bisexual and fertile but occasionally staminate with reduced ovaries. Discoid heads comprise only disk flowers. A radiant head is a variant of a discoid head, with peripheral disk flower corollas expanded, often bilateral. A ray flower corolla is bilateral, generally with a slender tube and flattened petal-like ray (single lip composed of generally 3 lobes). Ray flowers are generally pistillate or sterile (occasionally lacking styles). Radiate heads have peripheral ray flowers and central disk flowers. Disciform heads superficially resemble discoid heads, with pistillate or sterile flowers that lack rays, together with or separate from disk flowers. A ligulate flower is bisexual, with a bilateral, generally ephemeral corolla and 5-lobed ligule. Liguliflorous heads comprise only ligulate flowers. See glossary p. 31 for illustrations of family characteristics. Echinops sphaerocephalus L., Gaillardia aristata Pursh, Gaillardia pulchella Foug., Hymenothrix loomisii S.F. Blake, Tagetes erecta L., Thelesperma megapotamicum (Spreng.) Kuntze are waifs. Melampodium perfoliatum Kunth, historic urban waif. Ageratum conyzoides L., Guizotia abyssinica (L. f.) Cass., Santolina chamaecyparisus L., orth. var. are rare or uncommon escapes from cultivation. Dyssodia papposa, Ismelia carinata (Schousb.) Sch. Bip. [Chrysanthemum carinatum Schousb.], Mantisalca salmantica (L.) Briq. & Cavill. are historical or extirpated waifs in California. Inula helenium L. not documented in California. Taxa of Aster in TJM (1993) treated here in Almutaster, Eucephalus, Eurybia, Ionactis, Oreostemma, Sericocarpus, Symphyotrichum; Chamomilla in Matricaria; Cnicus in Centaurea; Conyza in Erigeron and Laennecia; Dugaldia in Hymenoxys; Erechtites in Senecio; Hymenoclea in Ambrosia; Lembertia in Monolopia; Osteospermum ecklonis in Dimorphotheca; Picris echioides in Helminthotheca; Prionopsis in Grindelia; Raillardiopsis in Anisocarpus and Carlquistia; Schkuhria multiflora in Bahia; Trimorpha in Erigeron; Venidium in Arctotis; Whitneya in Arnica. Taxa of Arida in TJM2 treated here in Leucosyris. —Scientific Editors: David J. Keil, Bruce G. Baldwin.
Unabridged note: Largest family of vascular plants in California and of eudicots globally.
Key to Asteraceae
Annual to subshrub (2)5–70(200) cm; proximal stem and leaves glabrous to variously hairy. Stem: 1, erect, or 2–25+, prostrate to ascending, simple or branched. Leaf: simple, alternate, often crowded proximally, petioled, generally ± elliptic to ovate or obovate, generally deeply 1–4-pinnately lobed, occasionally entire (then linear), lobes generally not or scarcely overlapping; distal generally ± reduced. Inflorescence: heads discoid or radiant, 1–25+ per stem, generally in terminal cyme-like cluster; peduncle generally erect, hairs generally as on phyllary bases; involucre generally <= 15 mm diam, cylindric to obconic or hemispheric; phyllaries in 1–2 ± = series, generally linear to lanceolate, persistent, tips generally ± flat, generally ± green; receptacle flat to rounded, glabrous, generally epaleate. Flower: 8–70+; corolla white, ± pink, or yellow, generally open during day; anthers generally exserted, tips lanceolate to ovate; style tips linear, minutely bristly. Fruit: ± club-shaped, generally not compressed, ± hairy; pappus 0, crown-like, or generally of (1)4–20 persistent, ± fringed scales in 1–4 series, scales often fewer and/or shorter on outer fruit.Key to Chaenactis
18 species: western North America. (Greek: gaping ray, for enlarged outer corollas of type sp.) [Morefield 2006 FNANM 21:400–414] Species of sect. Chaenactis hybridize, especially in Inner South Coast Ranges/s San Joaquin Valley, where identification can be difficult.
Previous taxon: Centromadia pungens subsp. pungens
Next taxon: Chaenactis alpigena
Citation for the whole project: Jepson Flora Project (eds.) 2013. Jepson eFlora, http://ucjeps.berkeley.edu/IJM.html, accessed on Aug 23 2014
Citation for this treatment: [Author of taxon treatment] 2013. Chaenactis, in Jepson Flora Project (eds.) Jepson eFlora, http://ucjeps.berkeley.edu/cgi-bin/get_IJM.pl?tid=370, accessed on Aug 23 2014
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