Jepson eFlora: Taxon page
Vascular Plants of California
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Poteridium annuum

Higher Taxonomy
Family: RosaceaeView DescriptionDichotomous Key
Common Name: ROSE FAMILY
Habit: Annual to tree, glandular or not. Leaf: simple to palmately or pinnately compound, generally alternate; stipules free to fused (0), persistent to deciduous. Inflorescence: cyme, raceme, panicle, cluster, or flowers 1; bractlets on pedicel ("pedicel bractlets") generally 0--3(many), subtended by bract or generally not. Flower: generally bisexual, radial; hypanthium free or fused to ovary, saucer- to funnel-shaped, subtending bractlets ("hypanthium bractlets") 0--5, alternate sepals; sepals generally 5; petals generally 5, free; stamens (0,1)5--many, anther pollen sacs generally 2; pistils (0)1--many, simple or compound, ovary superior to inferior, styles 1--5. Fruit: 1--many per flower, achene (fleshy-coated or not), follicle, drupe, or pome with generally papery core, occasionally drupe-like with 1--5 stones. Seed: generally 1--5 (per fruit, not per flower).
Genera In Family: 110 genera, +- 3000 species: worldwide, especially temperate; many cultivated for ornament, fruit, especially Cotoneaster, Fragaria, Malus, Prunus, Pyracantha, Rosa, Rubus. Note: Number of teeth is per leaf or leaflet, not per side of leaf or leaflet, except in Drymocallis.
eFlora Treatment Author: Daniel Potter & Barbara Ertter, family description, key to genera, treatment of genera by Daniel Potter, except as noted
Scientific Editor: Daniel Potter, Thomas J. Rosatti.
Genus: PoteridiumView Description 

Etymology: (Diminutive of Poterium)
eFlora Treatment Author: Daniel Potter & Barbara Ertter
Unabridged Reference: Kerr 2004 A phylogenetic and biogeographic analysis of Sanguisorbeae (Rosaceae), with emphasis on the Pleistocene radiation of the high Andean genus Polylepis. Ph.D. Dissertation Univ of Maryland.
Poteridium annuum (Nutt.) Spach
Habit: Annual, biennial, taprooted, nonglandular. Stem: generally ascending to erect, generally 10--70 cm. Leaf: alternate, odd-1-pinnately compound; basal withered at flower; largest cauline generally 3--12 cm; leaflets 4--7 per side, largest blade 5--20 mm, +- sessile, +- obovate-elliptic, lobes < 15, > 2/3 to midvein, linear. Inflorescence: spike, head-like, 5--35 mm, 5--10 mm wide, cylindric-ovoid, +- 10--50-flowered; peduncle 3--15 cm; pedicel bractlets 2, subtended by 1 bract, all 3 2--3 mm wide. Flower: bisexual; hypanthium urn-shaped, bractlets 0; sepals generally 4, 2--3 mm, ovate, green; petals 0; stamens generally 2, filaments thread-like; pistil 1, ovary superior, continuous to style at top, stigma +- bushy, exserted. Fruit: hypanthium enclosing achene, 2--4 mm, 4-angled, +- winged, hard, faces wrinkled. Chromosomes: 2n=14.
Ecology: Open, especially disturbed areas; Elevation: 225--1890 m. Bioregional Distribution: KR, CaRH, n&c SNH, n CCo, PR, MP; Distribution Outside California: to British Columbia, Montana. Flowering Time: Apr--Jul
Synonyms: Sanguisorba annua (Nutt.) Nutt. ex Torr. & A. Gray; Sanguisorba occidentalis Nutt. ex Torr. & A. Gray, inval.
Jepson eFlora Author: Daniel Potter & Barbara Ertter
Index of California Plant Names (ICPN; linked via the Jepson Online Interchange)

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Botanical illustration including Poteridium annuum

botanical illustration including Poteridium annuum

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Citation for this treatment: Daniel Potter & Barbara Ertter 2012, Poteridium annuum, in Jepson Flora Project (eds.) Jepson eFlora,, accessed on March 03, 2024.

Citation for the whole project: Jepson Flora Project (eds.) 2024, Jepson eFlora,, accessed on March 03, 2024.

Poteridium annuum
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©2009 Neal Kramer
Poteridium annuum
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©2018 Steve Matson
Poteridium annuum
click for enlargement
©2009 Neal Kramer
Poteridium annuum
click for enlargement
©2006 Steve Matson
Poteridium annuum
click for enlargement
©2006 Steve Matson

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Geographic subdivisions for Poteridium annuum:
KR, CaRH, n&c SNH, n CCo, PR, MP
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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.
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

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).