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Emex australis

SOUTHERN THREE-CORNERED JACK


Higher Taxonomy
Family: PolygonaceaeView DescriptionDichotomous Key
Common Name: BUCKWHEAT FAMILY
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: EmexView DescriptionDichotomous Key


Habit: Annual, glabrous; monoecious. Stem: decumbent to erect, 1--8 dm, base often +- red. Leaf: cauline, alternate, petioled; ocrea soon torn, falling; blade +- hastate to cordate. Staminate Inflorescence: axillary, terminal, raceme-like; flowers 1--8. Pistillate Inflorescence: axillary, spike-like; flowers 1--8. Staminate Flower: perianth parts 5--6, free; stamens 4--6. Pistillate Flower: perianth parts 6, fused; outer 3 spine-tipped in fruit, inner 3 tubercled; styles 3, free. Fruit: included, 2--4.5 mm, ovate, shiny, spines 3; perianth hardened. Chromosomes: 2n=20.
Etymology: (Latin: removal from Rumex) Note: Hybrids occur readily when species together; highly sterile when self-pollinated but can backcross with either parent to form viable seeds.
eFlora Treatment Author: Mihai Costea
Emex australis Steinh.
NATURALIZED
Stem: 1--5(6) dm. Leaf: petiole (0.5)1--6(15) cm; blade 1--5(9) cm, 0.5--3(6) cm wide. Fruit: perianth 3-angled, each face with 3--4 longitudinally elongated depressions, spines 3.5--6 mm.
Ecology: Coastal, sandy areas; Elevation: < 200 m. Bioregional Distribution: CCo; Distribution Outside California: introduced in Hawaii, West Indies, Africa, Asia, Australia; native to southern Africa. Flowering Time: May--Dec Note: Possibly an historical waif.
Jepson eFlora Author: Mihai Costea
Index of California Plant Names (ICPN; linked via the Jepson Online Interchange)
Noxious Weed listed on the CDFA Weed Pest Ratings table
View the CDFA Pest Rating page for Emex australis
Weed listed by Cal-IPC

Previous taxon: Emex
Next taxon: Emex spinosa

Botanical illustration including Emex australisbotanical illustration including Emex australis


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Citation for this treatment: Mihai Costea 2012, Emex australis, in Jepson Flora Project (eds.) Jepson eFlora, https://ucjeps.berkeley.edu/eflora/eflora_display.php?tid=24221, accessed on November 13, 2024.

Citation for the whole project: Jepson Flora Project (eds.) 2024, Jepson eFlora, https://ucjeps.berkeley.edu/eflora/, accessed on November 13, 2024.

No expert verified images found for Emex australis.



Geographic subdivisions for Emex australis:
CCo
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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 occurrence).






 

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

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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.
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CCH collections by month Flowering-Fruiting Monthly Counts

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).