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Vascular Plants of California
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Heterotheca sessiliflora subsp. sessiliflora

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: HeterothecaView DescriptionDichotomous Key

Habit: Annual to perennial herb, taprooted or with caudex or rhizome; herbage +- strigose-bristly or spreading-hairy, +- stalked-glandular, generally +- strongly aromatic. Stem: 1--many, ascending or erect, +- branched. Leaf: basal and cauline, alternate; proximal petioled or sessile, oblanceolate to ovate, petiole or blade base generally +- spreading-long-hairy; distal +- reduced. Inflorescence: +- flat-topped to raceme- or panicle-like; heads discoid or generally radiate; involucre +- cylindric to bell- or urn-shaped; phyllaries +- graduated in +- 3--7 series; receptacle flat to slightly convex, pitted, epaleate. Ray Flower: 0 or 10--40; ray yellow. Disk Flower: many; corolla yellow; anther tip narrowly triangular; style tips narrowly triangular, papillate. Fruit: obconic; ray fruit +- 3-angled, pappus 0 or of bristles; disk fruit compressed, outer pappus of few to many bristle-like scales 0.2--1 mm, inner of 30--45 bristles in 2--3 series, 3--10 mm.
Etymology: (Greek: different cases, for ray and disk fruits of some species)
eFlora Treatment Author: John C. Semple
Reference: Semple 2006 FNANM 20:230--256
Species: Heterotheca sessilifloraView Description 

Habit: Perennial herb generally 2--7(13) dm. Stem: decumbent to erect, branching in inflorescence, +- bristly, +- glandular, especially distally. Leaf: basal and proximal cauline subsessile, oblanceolate, tapered at base, entire, generally withered at flower, mid-cauline sessile, +- lanceolate, flat or wavy, +- densely bristly-strigose, +- densely glandular, distal generally reduced. Inflorescence: heads generally +- many in +- flat-topped or panicle-like cluster, generally not subtended by leaf-like bracts; involucre 8--14 mm, phyllaries in 4--6 series, +- sparsely strigose, +- sparsely to densely glandular. Ray Flower: 4--24; ray generally 7--15 mm. Disk Flower: 20--50; corolla 3--10 mm; lobes generally sparsely hairy, 0.25--1 mm. Fruit: 1.5--4.5 mm; ray and disk fruit similar, +- strigose; outer pappus 0.25--0.5 mm, inner 5--8(10) mm.
Note: Highly variable, especially in CW; subspecies +- merge where ranges overlap.
Heterotheca sessiliflora (Nutt.) Shinners subsp. sessiliflora
Habit: Plant generally moderately to densely bristly-strigose proximally, generally sparsely hairy and densely glandular distally. Leaf: wavy-margined, distal reduced, not stiff, green, hairs generally +- 1 mm. Inflorescence: heads few, subtended by leaf-like bracts. Disk Flower: 30--50; corolla lobes +- glabrous.
Ecology: Beaches, dunes, mud flats; Elevation: < 60 m. Bioregional Distribution: s CCo, SCo; Distribution Outside California: Baja California. Flowering Time: Jun--Sep
Synonyms: Heterotheca sessiliflora var. sessiliflora
Jepson eFlora Author: John C. Semple
Reference: Semple 2006 FNANM 20:230--256
Index of California Plant Names (ICPN; linked via the Jepson Online Interchange)
Listed on CNPS Rare Plant Inventory

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Botanical illustration including Heterotheca sessiliflora subsp. sessiliflora

botanical illustration including Heterotheca sessiliflora subsp. sessiliflora

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Citation for this treatment: John C. Semple 2012, Heterotheca sessiliflora subsp. sessiliflora, in Jepson Flora Project (eds.) Jepson eFlora,, accessed on June 12, 2024.

Citation for the whole project: Jepson Flora Project (eds.) 2024, Jepson eFlora,, accessed on June 12, 2024.

Heterotheca sessiliflora subsp. sessiliflora
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©2015 Keir Morse
Heterotheca sessiliflora subsp. sessiliflora
click for enlargement
©2015 Keir Morse
Heterotheca sessiliflora subsp. sessiliflora
click for enlargement
©2015 Keir Morse
Heterotheca sessiliflora subsp. sessiliflora
click for enlargement
©2015 Keir Morse
Heterotheca sessiliflora subsp. sessiliflora
click for enlargement
©2015 Keir Morse

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Geographic subdivisions for Heterotheca sessiliflora subsp. sessiliflora:
s CCo, SCo
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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 occurence).


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

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).