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Key to families | Table of families and genera

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Daniel Potter & Barbara Ertter, family description, key to genera; treatment of genera by Daniel Potter, except as noted

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).
110 genera, ± 3000 species: worldwide, especially temperate; many cultivated for ornamental, fruit, especially Cotoneaster, Fragaria, Malus, Prunus, Pyracantha, Rosa, Rubus. [Potter et al. 2007 Plant Syst Evol 266:5–43] Number of teeth is per leaf or leaflet, not per side of leaf or leaflet, except in Drymocallis. —Scientific Editors: Daniel Potter, Thomas J. Rosatti.
Unabridged references: [Robertson 1974 J Arnold Arbor 55:303–332, 344–401, 611–662]

Key to Rosaceae


1 sp. (Diminutive of Poterium)
Unabridged references: [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.]

P. annuum (Nutt.) Spach WESTERN BURNET
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.
2n=14. Open, especially disturbed areas; 225–1890 m. Klamath Ranges, High Cascade Range, n&c High Sierra Nevada, n Central Coast, Peninsular Ranges, Modoc Plateau; to British Columbia, Montana. [Sanguisorba annua (Nutt.) Nutt. ex Torr. & A. Gray; Sanguisorba occidentalis Nutt. ex Torr. & A. Gray, inval.] Apr–Jul [Online Interchange]

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Citation for the whole project: Jepson Flora Project (eds.) 2013. Jepson eFlora,, accessed on Nov 25 2015
Citation for this treatment: [Author of taxon treatment] 2013. Poteridium, in Jepson Flora Project (eds.) Jepson eFlora,, accessed on Nov 25 2015

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Geographic subdivisions indicated for the distribution of Poteridium annuum Markers link to CCH specimen records. If the markers are obscured, reload the page [or change window size and reload]. Yellow markers indicate records that may provide evidence for eFlora range revision or may have georeferencing or identification issues.
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.
Blue line denotes eFlora flowering time.