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

Ranunculus aquatilis var. diffusus

Higher Taxonomy
Family: RanunculaceaeView DescriptionDichotomous Key
Habit: Annual, perennial herb, woody vine [shrub], occasionally aquatic. Leaf: generally basal and cauline, alternate or opposite, simple or compound; petioles at base generally flat, occasionally sheathing or stipule-like. Inflorescence: cyme, raceme, panicle, or flowers 1. Flower: generally bisexual, generally radial; sepals 3--6(20), free, early-deciduous or withering in fruit, generally green; petals 0--many, generally free; stamens generally 5--many, staminodes generally 0; pistils 1--many, ovary superior, chamber 1, style 0--1, generally +- persistent as beak, ovules 1--many. Fruit: achene, follicle, berry, +- utricle in Trautvetteria, in aggregate or not, 1--many-seeded.
Genera In Family: +- 60 genera, 1700 species: worldwide, especially northern temperate, tropical mountains; many ornamental (Adonis, Aquilegia, Clematis, Consolida, Delphinium, Helleborus, Nigella). Toxicity: some highly TOXIC (Aconitum, Actaea, Delphinium, Ranunculus). Note: Taxa of Isopyrum in TJM (1993) moved to Enemion; Kumlienia moved to Ranunculus.
eFlora Treatment Author: Margriet Wetherwax & Dieter H. Wilken, family description, key to genera
Scientific Editor: Douglas H. Goldman, Bruce G. Baldwin.
Genus: RanunculusView DescriptionDichotomous Key

Common Name: BUTTERCUP
Habit: Annual to perennial herb, occasionally from stolons or caudices, terrestrial or aquatic; roots generally fibrous. Stem: prostrate to erect. Leaf: basal, cauline, or both, alternate, generally reduced upward; petiole base flat, stipule-like or not; basal, proximal cauline petioles generally long; blades simple to dissected or compound, entire to toothed. Inflorescence: cyme, axillary or terminal, 1--few-flowered. Flower: sepals 3--5(6), generally early-deciduous, generally green to yellow or purple; petals 0--17[(150)], shiny, generally yellow, occasionally white or purple, nectaries near base, pocket-like or with flap-like scale; anthers yellow; pistils generally many. Fruit: achene, compressed or not, +- spheric, disk-like (width 3--15 × depth), or lenticular (width 1--2 × depth), beaked.
Etymology: (Latin: diminutive of Rana, frog, from wet habitats)
eFlora Treatment Author: Alan T. Whittemore
Species: Ranunculus aquatilisView Description 

Habit: Perennial herb (5)20--80 cm, aquatic or creeping on mud, rooting at nodes. Leaf: submersed or floating and submersed; submersed generally 3--6-dissected; stipules tapered, united. Flower: receptacle bristly; sepals 5, spreading or reflexed, 2--4 mm, 1--2 mm wide, early-deciduous; petals 5, 4--7 mm, 1--5 mm wide, white or white with yellow claws; style 0.2--1.2 mm. Fruit: 15--many, body 1--2 mm, 0.8--1.4 mm wide, lenticular, wall thick, transversely wrinkled, beak persistent, thread-like.

Ranunculus aquatilis L. var. diffusus With.
Leaf: floating and submersed dissected into thread-like segments. Fruit: body 1--1.8 mm, 0.8--1.2 mm wide, beak 0.2--1.2 mm.
Ecology: Ponds, lakes, streams, river edges; Elevation: < 3200 m. Bioregional Distribution: CA-FP, GB; Distribution Outside California: North America, Eurasia, Australia. Flowering Time: Mar--Sep
Synonyms: Ranunculus aquatilis var. capillaceus (Thuill.) DC.; Ranunculus aquatilis var. harrisii L.D. Benson; Ranunculus aquatilis var. longirostris (Godr.) G. Lawson; Ranunculus aquatilis var. subrigidus (W.B. Drew) Breitung; Ranunculus circinatus Sibth. var. subrigidus (W.B. Drew) L.D. Benson; Ranunculus longirostris Godr.; Ranunculus subrigidus W.B. Drew; Ranunculus trichophyllus Chaix; Ranunculus trichophyllus var. trichophyllus
Jepson eFlora Author: Alan T. Whittemore
Index of California Plant Names (ICPN; linked via the Jepson Online Interchange)

Previous taxon: Ranunculus aquatilis var. aquatilis
Next taxon: Ranunculus arvensis

Name Search

Botanical illustration including Ranunculus aquatilis var. diffusus

botanical illustration including Ranunculus aquatilis var. diffusus

Please use this Google Form for Contact/Feedback

Citation for this treatment: Alan T. Whittemore 2012, Ranunculus aquatilis var. diffusus, in Jepson Flora Project (eds.) Jepson eFlora,, accessed on April 14, 2024.

Citation for the whole project: Jepson Flora Project (eds.) 2024, Jepson eFlora,, accessed on April 14, 2024.

Ranunculus aquatilis  
var. diffusus
click for enlargement
©2008 Keir Morse
Ranunculus aquatilis  
var. diffusus
click for enlargement
©2007 Steve Matson
Ranunculus aquatilis  
var. diffusus
click for enlargement
©2009 Keir Morse
Ranunculus aquatilis  
var. diffusus
click for enlargement
©2007 George W. Hartwell
Ranunculus aquatilis  
var. diffusus
click for enlargement
©2017 Neal Kramer

More photos of Ranunculus aquatilis var. diffusus
in CalPhotos

Geographic subdivisions for Ranunculus aquatilis var. diffusus:
1. You can change the display of the base map layer control box in the upper right-hand corner.
2. County and Jepson Region polygons can be turned off and on using the check boxes.
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).


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).