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Vascular Plants of California
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Oxytheca watsonii

Higher Taxonomy
Family: PolygonaceaeView DescriptionDichotomous Key
Habit: Annual to shrub [tree]. Stem: nodes swollen or not. Leaf: simple, basal or cauline, generally alternate; ocreae present or 0, generally scarious, persistent or not. Inflorescence: flower clusters in axillary to terminal cyme-, panicle-, raceme-, spike-, umbel- or head-like arrangements, entire inflorescence or main inflorescence branches generally subtended by bracts ("inflorescence bracts"); peduncles present or 0; flower clusters in Eriogoneae-Eriogonoideae subtended by involucre of >= 1 free or +- fused, sometimes awn-tipped bracts ("involucre bracts") or, in Polygonoideae and rarely in Eriogonoideae, not (if bracts completely fused, involucre "tubular"); pedicels in Eriogoneae each often subtended by 2 free, transparent, linear bractlets or in Polygonoideae all subtended by 2+ fused, membranous, wide bractlets. Flower: generally bisexual, small, 1--200 per node; perianth parts 2--6, generally in 2 whorls, free or basally fused, generally petal-like, often +- concave adaxially, often darker at midvein, often turning +- red or +- brown in age; stamens [1]3 or 6--9 in 2 whorls; ovary superior, 1-chambered, ovule 1, styles 1--3. Fruit: achenes, included in or exserted from perianth, generally 3-angled, ovoid or elliptic, generally glabrous.
Genera In Family: 48 genera, +- 1200 species: worldwide, especially northern temperate; some cultivated for food (Coccoloba, sea-grape; Fagopyrum, Rheum, Rumex) or ornamental (Antigonon, lovechain; Coccoloba; Muehlenbeckia; Persicaria; Polygonum), a few timbered (Coccoloba; Triplaris). Several (Emex; Fallopia; Persicaria; Polygonum; Rumex) are weeds. Note: Treatment of genera in Eriogonoideae based on monographic work of James L. Reveal. Involucre number throughout is number (1--many) per ultimate grouping, at tips of ultimate branches; flower number is per flower cluster or involucre, unless otherwise stated. Fagopyrum esculentum Moench not naturalized, considered an historical waif (or garden weed +- presently), therefore not treated.
eFlora Treatment Author: Mihai Costea, except as noted
Scientific Editor: Thomas J. Rosatti, Bruce G. Baldwin.
Genus: OxythecaView DescriptionDichotomous Key

Habit: Annual, erect to spreading, glabrous or sparsely glandular. Leaf: basal, linear to narrow, awns 0; ocreae 0. Inflorescence: terminal, cyme-like; peduncles 0 or erect or reflexed; involucres 1, tubular, teeth (3)4, generally glabrous, awned. Flower: 2--10, glabrous or hairy and glandular; perianth white to rose or green-yellow, lobes 6, entire; stamens 9. Fruit: brown to maroon, generally elliptic, glabrous; embryo curved.
Species In Genus: 3 species: temperate western North America, southern South America. Etymology: (Greek: sharp case, for awned involucre) Note: Other taxa in TJM (1993) moved to Acanthoscyphus, Sidotheca.
eFlora Treatment Author: James L. Reveal & Thomas J. Rosatti
Reference: Ertter 1980 Brittonia 32:70--102
Oxytheca watsonii Torr. & A. Gray
Stem: erect to spreading, 0.5--2.5 dm, 0.4--4 dm diam. Leaf: blades 0.7--4 cm, (0.1)0.5--1.2 cm wide, hairy and glandular adaxially, less so or glabrous abaxially. Inflorescence: bracts generally 3, free, awns 1--3 mm; peduncles reflexed, 2--5 mm, or generally 0; involucre 1.5--2 mm, lobes 4, awns 2.5--3 mm, +- red. Flower: 2--4(7), 1--1.5 mm; perianth white to pink. Fruit: 1--1.5 mm. Chromosomes: n=20.
Ecology: Sand; Elevation: 1200--2000 m. Bioregional Distribution: se W&I (Santa Rosa Hills, Inyo Co.); Distribution Outside California: Nevada. Flowering Time: Jun--Oct
Synonyms: Eriogonum cuspidatum S. Stokes
Jepson eFlora Author: James L. Reveal & Thomas J. Rosatti
Reference: Ertter 1980 Brittonia 32:70--102
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 Oxytheca watsonii

botanical illustration including Oxytheca watsonii


Citation for this treatment: James L. Reveal & Thomas J. Rosatti 2012, Oxytheca watsonii, in Jepson Flora Project (eds.) Jepson eFlora, eflora_display.php?tid=35740, accessed on January 22, 2020.

Citation for the whole project: Jepson Flora Project (eds.) 2020, Jepson eFlora,, accessed on January 22, 2020.

Oxytheca watsonii
click for enlargement
© 2007 Steve Matson
Oxytheca watsonii
click for enlargement
© 2007 Steve Matson
Oxytheca watsonii
click for enlargement
© 2007 Steve Matson
Oxytheca watsonii
click for enlargement
© 2007 Steve Matson
Oxytheca watsonii
click for enlargement
© 2007 Steve Matson
Oxytheca watsonii
click for enlargement
© 2007 Steve Matson

More photos of Oxytheca watsonii in CalPhotos

Geographic subdivisions for Oxytheca watsonii:
se W&I (Santa Rosa Hills, Inyo Co.)
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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).


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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).