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Petrophytum caespitosum

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 ornamental, 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: PetrophytumView Description 

Habit: Shrub, matted, scapose. Leaf: crowded, simple, evergreen, generally +- oblanceolate, entire. Inflorescence: +- spike-like; pedicel bractlets 0. Flower: hypanthium bractlets 0; sepals persistent; petals white; stamens 20--40; pistils generally 5, simple, ovary superior, hairy, styles thread-like. Fruit: follicles, dehiscing along both sutures. Seed: 1--several, linear.
Species In Genus: +- 4 species: western North America. Etymology: (Greek: rock pl)
eFlora Treatment Author: Daniel Potter & Thomas J. Rosatti

Petrophytum caespitosum (Nutt.) Rydb.
Habit: Plant 3--8 dm wide; rosettes many. Leaf: 1--3-veined abaxially. Inflorescence: 1--5 cm, dense; peduncle 3--10 cm, bracted. Flower: sepals +- 1.5 mm, narrow-ovate, acute; petals +- 1.5 mm, generally obtuse; style +- 3 mm. Fruit: +- 2 mm. Seed: 1--2, +- 1.5 mm, linear to obovoid, brown, smooth.

Synonyms: Petrophyton caespitosum (Nutt.) Rydb., orth. var.
eFlora Treatment Author: Daniel Potter & Thomas J. Rosatti
Jepson Online Interchange
Key to Petrophytum caespitosum

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botanical illustration including Petrophytum caespitosum


Citation for this treatment: Daniel Potter & Thomas J. Rosatti 2016. Petrophytum caespitosum, in Jepson Flora Project (eds.) Jepson eFlora,, accessed on May 01, 2016.

Citation for the whole project: Jepson Flora Project (eds.) 2016. Jepson eFlora,, accessed on May 01, 2016.

Petrophytum caespitosum subsp. caespitosum
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© 2005 James M. Andre
Petrophytum caespitosum
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© 2007 California Academy of Sciences
Petrophytum caespitosum
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© 2009 Aaron Schusteff
Petrophytum caespitosum subsp. acuminatum
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© 2012 Gary A. Monroe
Petrophytum caespitosum
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© 2009 Aaron Schusteff
Petrophytum caespitosum subsp. caespitosum
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© 2009 Barry Breckling

More photos of Petrophytum caespitosum in CalPhotos

Geographic subdivisions for Petrophytum caespitosum:
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.