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Vascular Plants of California
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Oreostemma peirsonii

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, Eucephalus, 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; Whitneya in Arnica. Amauriopsis in TJM2 (2012) treated here in Hymenothrix; Arida in Leucosyris; Bahia in Picradeniopsis.
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: OreostemmaView DescriptionDichotomous Key

Common Name: ASTER
Habit: Perennial herb, from taproot or thick rhizome, sometimes with branched caudex. Stem: decumbent-ascending to erect, unbranched, +- scape-like, generally distally finely loose-tomentose, glandless or stalked-glandular. Leaf: most basal in rosette, sessile, linear to oblanceolate, 3-veined, entire, glabrous to sparsely long-soft-hairy or stalked-glandular. Inflorescence: heads radiate, 1; involucre broadly top-shaped; phyllaries +- equal or graduated in (2)3--4 series, generally +- purple, linear to linear-elliptic or oblanceolate, leaf-like in texture (or proximal margins +- hardened), glabrous to loose-tomentose; receptacle flat, shallowly pitted, epaleate. Ray Flower: 10--40; corolla +- white to purple. Disk Flower: corolla tubular, yellow; anther tip ovate-triangular; style branch appendages lance-linear, 1.5--2.2 mm. Fruit: 4--5 mm, narrowly cylindric, +- brown, ribs 5--10, raised, faces glabrous or sparsely short-strigose; pappus +- white, of minutely barbed bristles in 1 series, sometimes also with few short bristles or hairs.
Species In Genus: 3 species: western United States and adjacent Canada. Etymology: (Greek: mountain + crown)
Unabridged Note: Oreostemma is distinguished by a basal rosette of narrow, 3-veined leaves, solitary heads on - scapose stems, top-shaped involucres with (2)3--4 series of +- equal, evenly herbaceous phyllaries, pink to purple rays, greatly elongate style-branch appendages, and cylindric fruits.
eFlora Treatment Author: Guy L. Nesom
Reference: Nesom 2006 FNANM 20:359--361
Unabridged Reference: Nesom 1993 Phytologia 74:305--316
Oreostemma peirsonii (Sharsm.) G.L. Nesom
Habit: Stems, phyllaries, and often leaves densely short-stalked-glandular, sparsely long-soft-hairy or not. Stem: 2--7 cm. Leaf: linear. Inflorescence: phyllaries leaf-like in texture and color throughout or proximally tan, slightly hardened, outer proximally 0.8--1.2 mm wide, 1-veined. Ray Flower: corolla 12--16 mm. Disk Flower: corolla 5.5--8 mm. Fruit: slightly hairy.
Ecology: Rocky slopes, ridges, dry meadows; Elevation: 3000--3800 m. Bioregional Distribution: s SNH. Flowering Time: Jul--Sep
Synonyms: Aster peirsonii Sharsm.;
Jepson eFlora Author: Guy L. Nesom
Reference: Nesom 2006 FNANM 20:359--361
Unabridged Reference: Nesom 1993 Phytologia 74:305--316
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Citation for this treatment: Guy L. Nesom 2012, Oreostemma peirsonii, in Jepson Flora Project (eds.) Jepson eFlora,, accessed on December 14, 2018.

Citation for the whole project: Jepson Flora Project (eds.) 2018, Jepson eFlora,, accessed on December 14, 2018.

No expert verified images found for Oreostemma peirsonii.

Geographic subdivisions for Oreostemma peirsonii:
s SNH.
Markers link to CCH specimen records. Yellow markers indicate records that may provide evidence for eFlora range revision or may have georeferencing or identification issues. Purple markers indicate specimens collected from a garden, greenhouse, or other non-wild location.
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).

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