Plant Assessment Form

Carthamus lanatus

Synonyms: Carthamus lanatus ssp. lanatus

Common Names: woolly distaff thistle; false starthistle; saffron thistle; woolly safflower; woolly starthistle

Evaluated on: 3/22/05

List committee review date: 08/07/2005

Re-evaluation date:


Elizabeth Brusati, project manager
California Invasive Plant Council
1442A Walnut St. #462, Berkeley, CA 94709
Joseph DiTomaso
University of California-Davis
Dept. Plant Sci., Mail Stop 4, Davis, CA 95616

List commitee members

Carla Bossard
John Randall
Carri Pirosko
Dan Gluesenkamp
Gina Skurka
Brianna Richardson

General Comments

No general comments for this species

Table 2. Criteria, Section, and Overall Scores

Overall Score? High
Alert Status? No Alert
Documentation? 3 out of 5
Score Documentation
1.1 ?Impact on abiotic ecosystem processes U
Four-part score UAAD Total Score
1.2 ?Impact on plant community A. Severe Reviewed Scientific Publication
1.3 ?Impact on higher trophic levels A. Severe Reviewed Scientific Publication
1.4 ?Impact on genetic integrity D. None Other Published Material
2.1 ?Role of anthropogenic and natural disturbance in establishment B. Moderate Reviewed Scientific Publication
Total Points
13 Total Score B
2.2 ?Local rate of spread with no management A. Increases rapidly Anecdotal
2.3 ?Recent trend in total area infested within state A. Increasing rapidly Other Published Material
2.4 ?Innate reproductive potential
(see Worksheet A)
B. Moderate Other Published Material
2.5 ?Potential for human-caused dispersal C. Low Other Published Material
2.6 ? Potential for natural long-distance dispersal C. Rare Other Published Material
2.7 ?Other regions invaded C. Already invaded Reviewed Scientific Publication
3.1 ?Ecological amplitude/Range
(see Worksheet C)
B. Moderate Other Published Material
Total Score C
3.2 ?Distribution/Peak frequency
(see Worksheet C)
D. Very low Observational

Table 3. Documentation

Scores are explained in the "Criteria for Categorizing Invasive Non-Native Plants that Threaten Wildlands".

Section 1: Impact
Question 1.1 Impact on abiotic ecosystem processes? U
Identify ecosystem processes impacted:

<p>No information available. May impact the hydrology of the infested sites. Water loss increase on site because foliage is above ground level and does not slow the flow of water down slope as would grass species.</p>

Sources of information:

<p>DiTomaso, observational</p>

Question 1.2 Impact on plant community composition,
structure, and interactions?
A Reviewed Scientific Publication
Identify type of impact or alteration:

<p>Outcompetes other species for moisture, light,and nutrients. Restricts growth of other species in low-nutrient soils (1). Forms dense stands (2). Large seeds and flat rosettes give it an early growth advantage over other species (3).</p>

Sources of information:

<p>1. Peirce, J. R. 1992. The biology of Australian weeds: 23. Carthamus lanatus L. Plant Protection Quarterly 7(3): 86-95. 2. Anonymous. 1998. Woolly Distaff Thistle Control. Marin Agricultural Land Trust, Technical Bulletin 3. Sindel, B. M. 1991. A review of the ecology and control of thistles in Australia. Weed Res 31(4): 189-201.</p>

Question 1.3 Impact on higher trophic levels? A Reviewed Scientific Publication
Identify type of impact or alteration:

<p>Causes injury to mouths and feet of livestock. Impedes passage of animals. Little or no feed or grazing value (1). Displaces palatable plants, decreasing the value of rangeland (2).</p>

Sources of information:

<p>1. Peirce 1992 2. Anonymous 1998</p>

Question 1.4 Impact on genetic integrity? D Other Published Material

<p>None No native Carthamnus species in California</p>

Sources of information:

<p>Hickman, J. C. (ed.) 1993. The Jepson Manual, Higher Plants of California. University of California Press. Berkeley, CA enter text here</p>

Section 2: Invasiveness
Question 2.1 Role of anthropogenic and natural disturbance
in establishment?
A Anecdotal
Describe role of disturbance:

<p>Inhabits disturbed areas, especially where the soil has been disturbed or the pasture weakened by overgrazing (1, 2).</p>

Sources of information:

<p>1. Burrill, L. C. 1992. Distaff thistle. Pacfic Northwest Extension Publication. PNW 420. 2. Peirce 1992</p>

Question 2.2 Local rate of spread with no management? A Anecdotal
Describe rate of spread:

<p>Numerous anecdotal reports indicate rapid spread of this plant in the coastal counties.</p>

Sources of information:

Question 2.3 Recent trend in total area infested within state? A Other Published Material
Describe trend:

<p>Spreading rapidly in Marin County (1) and central north coast area (2).</p>

Sources of information:

<p>1. Anonymous 1998 2. DiTomaso and Healy in prep</p>

Question 2.4 Innate reproductive potential? B Other Published Material
Describe key reproductive characteristics:

<p>Winter annual. Germinates after first spring rains. Plants flower late spring through summer, with seed produced in late summer (1). Plants can produce as many as 255 viable seeds (2). Most seeds germinate within two years but can remain viable after eight years under field conditions (3, 4). If mowed too early in season, can regrow and produce more flowers, but late season mowing probably controls plant (1).</p>

Sources of information:

<p>1. DiTomaso and Healy in prep. Weeds of California and Other Western States. 2. Peirce 1992 3. Groves, R. H. and P. E. Kaye. 1989. Germination and Phenology of Seven Introduced Thistle Species in Southern Australia. Australian Journal of Botany 37(4): 351-359 4. Quinlivan B.J., Peirce J.R. 1968. The Long-term Field Germination of Saffron Thistle (Carthamus lanatus L.) and the Life Span of Dormant Seeds in the Geraldton Region, W.A. The Journal of the Australian Institute of Agricultural Science. Volume unknown: December 1968, pp. 231-232.</p>

Question 2.5 Potential for human-caused dispersal? C Other Published Material
Identify dispersal mechanisms:

<p>A common contaminent of grain. Seeds can attach to clothing (1). Seed can be dispersed on vehicles and by livestock (2). These mechanisms may contribute to spread but are probably not common.</p>

Sources of information:

<p>1. Peirce 1992 2. DiTomaso and Healy in prep</p>

Question 2.6 Potential for natural long-distance dispersal? C Other Published Material
Identify dispersal mechanisms:

<p>Seeds can be dispersed by water (1). Not dispersed by wind, but can attach to animal fur (2). Vast majority of seed likely fall within a few feet of the parent plant.</p>

Sources of information:

<p>1. DiTomaso and Healy in prep 2. Peirce 1992</p>

Question 2.7 Other regions invaded? C Reviewed Scientific Publication
Identify other regions:

<p>Native to Mediterranean. A noxious weed in Australia, where it is considered the worst weed in New South Wales (1, 2). Spread to Oregon from California (3). Also present in Texas and Oklahoma (4).</p>

Sources of information:

<p>1. Peirce 1992 2. Briese, D. T. 1988. Weed Status of Twelve Thistle Species in New South Wales Australia. Plant Protection Quarterly 3(4): 135-141. 3. Burrill 1992 4. DiTomaso and Healy in prep.</p>

Section 3: Distribution
Question 3.1 Ecological amplitude/Range? B Other Published Material

Subspecies lanatus has been in California since at least 1891. Abundant in dry grasslands of the coastal areas of California. Also found a middle elevation of Sierra Nevada, in areas disturbed by gold mining (1). Present in northwestern California, central-western CA, central Sierra Nevada, southern North Coast, to 1100m (2).

Sources of information:

1. Fuller, T. C. 1979. Ecology of some Californian weeds that also occur in Australia. Proceedings of the Seventh Conference of the Asian-Pacific Weed Society, pp. 391-393. (cited in Peirce 1992)

Question 3.2 Distribution/Peak frequency? D Observational
Describe distribution:

More common in the Central Coast than in Southern California. Also expanding in the North Coast region.

Sources of information:

DiTomaso, observational. Dan Gluesenkamp, Audubon Canyon Ranch, pers. obs. Carla Bossard, St. Mary's College, pers. obs.

Worksheet A - Innate reproductive potential

Reaches reproductive maturity in 2 years or less Yes
Dense infestations produce >1,000 viable seed per square meter No
Populations of this species produce seeds every year. Yes
Seed production sustained over 3 or more months within a population annually No
Seeds remain viable in soil for three or more years Yes
Viable seed produced with both self-pollination and cross-pollination Unknown
Has quickly spreading vegetative structures (rhizomes, roots, etc.) that may root at nodes No
Fragments easily and fragments can become established elsewhere No
Resprouts readily when cut, grazed, or burned No
Total points: 4
Total unknowns: 1
Total score: B?

Related traits:

Worksheet B - Arizona Ecological Types is not included here

Worksheet C - California Ecological Types

(sensu Holland 1986)
Major Ecological Types Minor Ecological Types Code?
Marine Systemsmarine systems
Freshwater and Estuarine lakes, ponds, reservoirs
Aquatic Systemsrivers, streams, canals
Scrub and Chaparralcoastal bluff scrub
coastal scrub
Sonoran desert scrub
Mojavean desert scrub (incl. Joshua tree woodland)
Great Basin scrub
chenopod scrub
montane dwarf scrub
Upper Sonoran subshrub scrub
Grasslands, Vernal Pools, Meadows, and other Herb Communitiescoastal prairieD, < 5%
valley and foothill grasslandD, < 5%
Great Basin grassland
vernal pool
meadow and seep
alkali playa
pebble plain
Bog and Marshbog and fen
marsh and swamp
Riparian and Bottomland habitatriparian forest
riparian woodland
riparian scrub (incl.desert washes)
Woodlandcismontane woodlandD, < 5%
piñon and juniper woodland
Sonoran thorn woodland
Forestbroadleaved upland forest
North Coast coniferous forest
closed cone coniferous forest
lower montane coniferous forest
upper montane coniferous forest
subalpine coniferous forest
Alpine Habitatsalpine boulder and rock field
alpine dwarf scrub
Amplitude (breadth): B
Distribution (highest score): D

Infested Jepson Regions

Click here for a map of Jepson regions

  • Cascade Range
  • Central West
  • Great Valley
  • Modoc Plateau
  • Northwest
  • Sierra Nevada
  • Southwest