Jepson eFlora: Taxon page
Vascular Plants of California
Key to families | Table of families and genera
Previous taxon Index to accepted names and synonyms:
| A | B | C | D | E | F | G | H | I | J | K | L | M |
| N | O | P | Q | R | S | T | U | V | W | X | Y | Z |
Next taxon

Sium suave

Higher Taxonomy
Family: Apiaceae (Umbelliferae)View DescriptionDichotomous Key
Habit: Annual to perennial herb [shrub, tree], generally from taproot. Stem: generally +- scapose, generally ribbed, hollow. Leaf: basal and generally cauline, generally alternate; stipules generally 0; petiole base generally sheathing stem; blade generally much dissected, occasionally compound. Inflorescence: umbel or head, simple or compound, generally peduncled; bracts present in involucres or 0; bractlets generally present in "involucels". Flower: many, small, generally bisexual (or some staminate), generally radial (or outer bilateral); calyx 0 or lobes 5, small; petals 5, free, generally ovate or spoon-shaped, generally incurved at tips, generally +- ephemeral; stamens 5; pistil 1, ovary inferior, 2-chambered, generally with a +- conic, persistent projection or platform at tip subtending 2 free styles. Fruit: 2 dry, 1-seeded halves (= mericarps), separating from each other but generally +- persistent to central axis; ribs on halves 5, 2 marginal, 3 to back; oil tubes 1--several per interval between ribs.
Genera In Family: 300 genera, 3000 species: +- worldwide, especially temperate; many cultivated for food or spice (e.g., Carum, caraway; Daucus; Petroselinum); Bupleurum lancifolium Hornem. is historical garden weed; some toxic (e.g., Conium). Note: Mature fruit generally critical in identification, shape given in outline. Hydrocotyle moved to Araliaceae, Orogenia moved to Lomatium, Sphenosciadium moved to Angelica. Petroselinum crispum (Mill.) A.W. Hill is a waif.
eFlora Treatment Author: Lincoln Constance & Margriet Wetherwax, except as noted
Scientific Editor: Douglas H. Goldman, Bruce G. Baldwin.
Genus: SiumView Description 

Habit: Perennial herb, glabrous; roots clustered, fibrous or +- tuberous. Stem: erect or ascending, branched. Leaf: blade oblong to ovate, 1-pinnate, occasionally 2-pinnate when submerged, leaflets distinct, serrate, irregularly cut to pinnately lobed. Inflorescence: umbels compound, generally opposite a leaf; bracts, bractlets leaf-like, generally reflexed, conspicuous; rays, pedicels many, spreading-ascending. Flower: occasionally +- bilateral; calyx lobes 0 or minute; petals wide, white, narrowed at tips, outer +- > others. Fruit: ovate to round, +- compressed side-to-side; ribs prominent, +- equal, corky; oil tubes 1--3 per rib-interval; fruit axis entire or divided to base, adhering to fruit halves or not. Seed: face flat. Chromosomes: 2n=12.
Species In Genus: +- 10 species: North America, Eurasia, Africa. Etymology: (Greek: for an aquatic member of family)
eFlora Treatment Author: Lincoln Constance & Margriet Wetherwax
Sium suave Walter
Habit: Plant 6--12 dm, stout. Leaf: petiole 1--8 dm, segmented; blade 6--25 cm, 7--18 cm wide, leaflets 1--4 cm, linear or lanceolate, serrate, irregularly cut. Inflorescence: peduncle 4--10 cm; bracts 6--10, 3--15 mm, linear or lanceolate, acute, entire to irregularly cut; bractlets 4--8, 1--3 mm, lance-linear; rays 10--20, 1.5--3 cm, +- equal, slender; pedicels 3--5 mm. Fruit: 2--3 mm wide. Chromosomes: 2n=12.
Ecology: Swamps, marshes, streambanks; Elevation: < 2350 m. Bioregional Distribution: CaRH, c SNH, deltaic GV, GB; Distribution Outside California: to British Columbia, eastern North America; eastern Asia. Flowering Time: Jul--Aug
Jepson eFlora Author: Lincoln Constance & Margriet Wetherwax
Index of California Plant Names (ICPN; linked via the Jepson Online Interchange)

Previous taxon: Sium
Next taxon: Spermolepis

Name Search

Botanical illustration including Sium suave

botanical illustration including Sium suave


Citation for this treatment: Lincoln Constance & Margriet Wetherwax 2012, Sium suave, in Jepson Flora Project (eds.) Jepson eFlora,, accessed on April 14, 2021.

Citation for the whole project: Jepson Flora Project (eds.) 2021, Jepson eFlora,, accessed on April 14, 2021.

Sium suave
click for enlargement
© 2016 Keir Morse
Sium suave
click for enlargement
© 2016 Keir Morse
Sium suave
click for enlargement
© 2016 Keir Morse
Sium suave
click for enlargement
© 2016 Keir Morse
Sium suave
click for enlargement
© 2016 Keir Morse
Sium suave
click for enlargement
© 2016 Keir Morse

More photos of Sium suave in CalPhotos

Geographic subdivisions for Sium suave:
CaRH, c SNH, deltaic GV, GB
1. You can change the display of the base map and layers by clicking on the layer control box in the upper right-hand corner.
2. California county polygons can be turned off and on in the layer control box.
3. Filling of Jepson subdivision polygons can be turned off and on in the layer control box.
4. Moving the cursor over any numbered cluster will show the range boundary of the included specimens (with a blue polygon).
5. Marker clustering can be turned off by clicking this link:      Marker Clustering OFF
WARNING: Turning this off might cause maps with large numbers of specimens to load slowly.
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).


View elevation by latitude chart

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).