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Vascular Plants of California
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Malacothrix stebbinsii

Higher Taxonomy
Family: Asteraceae (Compositae)View DescriptionDichotomous Key
Habit: 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 (involucre 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.
Genera In Family: +- 1500 genera, 23000 species: worldwide, many habitats. Note: 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, Doellingeria, Eurybia, Ionactis, Oreostemma, Sericocarpus, Symphyotrichum; Chamomilla in Matricaria; Bahia in Hymenothrix; 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 Picradeniopsis; Trimorpha in Erigeron; Venidium in Arctotis; Viguiera in Aldama and Bahiopsis; Whitneya in Arnica. Amauriopsis in TJM2 (2012) treated here in Hymenothrix; Arida in Leucosyris; Bahia in Picradeniopsis; Eucephalus in Doellingeria.
Unabridged Note: Largest family of vascular plants in California and of eudicots globally.
eFlora Treatment Author: David J. Keil, except as noted
Scientific Editor: David J. Keil, Bruce G. Baldwin.
Genus: MalacothrixView DescriptionDichotomous Key

Habit: Annual, perennial herb, < 70 (200) cm; sap milky. Stem: generally +- branched, generally erect, generally glabrous. Leaf: generally basal and cauline, alternate, sessile, sometimes reduced distally on stem, entire, toothed, or +- deeply pinnately lobed or divided. Inflorescence: heads liguliflorous; involucre generally bell-shaped; phyllaries in 3--6 series, mid-stripe green or +- red; receptacle flat to convex, shallowly pitted, glabrous or with fragile, smooth bristles < 5 mm, epaleate. Flower: corolla yellow or white, readily withering; ligules of outermost flowers exserted 1--15 mm, generally +- red- or purple-striped abaxially. Fruit: 0.9--4 mm, +- fusiform, tip truncate, generally smooth; ribs 15 (5 generally prominent, 10 +- obscure), generally extending to tip; outer pappus 0 or of teeth < 0.5 mm, or rounded-toothed crown, and 0--6 smooth, persistent bristles, inner pappus of 12--32 bristles fused at base, readily deciduous, minutely barbed proximally.
Etymology: (Greek: soft hair) Note: Anisocoma, Atrichoseris, and Calycoseris perhaps best placed here (Lee et al. 2003 Syst Bot 28:616--626).
eFlora Treatment Author: W.S. Davis
Reference: Davis 2006 FNANM 19:310--321
Malacothrix stebbinsii W.S. Davis & P.H. Raven
Habit: Annual <= 60 cm. Stem: 1--5+, +- erect, branched distally, generally glabrous. Leaf: basal not fleshy, obovate, with 3--5 pairs of lobes; cauline reduced distally on stem, proximally +- 2--4-lobed. Inflorescence: heads generally few in open cyme- or panicle-like clusters; involucre 6--10 mm; outer phyllaries +- 1/2 inner, lanceolate to ovate, glabrous; receptacle glabrous. Flower: corolla generally 6--8 mm, white or pale yellow, ligules of outermost flowers exserted 1--2 mm. Fruit: 1.7--2.3 mm, ribs +- equal, 0 near tip; outer pappus of narrow teeth, bristles 1(2). Chromosomes: 2n=28.
Ecology: Gravelly soils on flats, gullies, streambeds, streambanks; Elevation: 300--1300 m. Bioregional Distribution: SNE, D; Distribution Outside California: Nevada, Arizona. Flowering Time: Mar--May
Jepson eFlora Author: W.S. Davis
Reference: Davis 2006 FNANM 19:310--321
Index of California Plant Names (ICPN; linked via the Jepson Online Interchange)

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Botanical illustration including Malacothrix stebbinsiibotanical illustration including Malacothrix stebbinsii

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Citation for this treatment: W.S. Davis 2012, Malacothrix stebbinsii, in Jepson Flora Project (eds.) Jepson eFlora,, accessed on July 13, 2024.

Citation for the whole project: Jepson Flora Project (eds.) 2024, Jepson eFlora,, accessed on July 13, 2024.

Malacothrix stebbinsii
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©2019 Dylan Neubauer
Malacothrix stebbinsii
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©2004 James M. Andre
Malacothrix stebbinsii
click for image enlargement
©2004 James M. Andre
Malacothrix stebbinsii
click for image enlargement
©2019 Dylan Neubauer

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Geographic subdivisions for Malacothrix stebbinsii:
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map of distribution 1

(Note: any qualifiers in the taxon distribution description, such as 'northern', 'southern', 'adjacent' etc., are not reflected in the map above, and in some cases indication of a taxon in a subdivision is based on a single collection or author-verified occurrence).


Data provided by the participants of the  Consortium of California Herbaria.

View all CCH records
All markers link to CCH specimen records. The original determination is shown in the popup window.
Blue markers indicate specimens that map to one of the expected Jepson geographic subdivisions (see left map). Purple markers indicate specimens collected from a garden, greenhouse, or other non-wild location.
Yellow markers indicate records that may provide evidence for eFlora range revision or may have georeferencing or identification issues.

CCH collections by month Flowering-Fruiting Monthly Counts

Duplicates counted once; synonyms included.
Species do not include records of infraspecific taxa, if there are more than 1 infraspecific taxon in CA.
Blue line denotes eFlora flowering time (fruiting time in some monocot genera).