Lathyrus nissolia -- California

Evaluation Summary

photo by Jutta Burger

Evaluation Date: 2022-08-22

Screener: Jutta Burger

Plant: Lathyrus nissolia

Common Name(s):

grass vetchling, grassy vetch, grass pea

State: California

PRE Score: 9

Questions Answered: 20

Screener Confidence (%): 72

Executive Summary

Lathyrus nissolia (grass vetchling, grass pea) is an annual herb in the pea family that is native to parts of Europe, North Africa, and the Mideast. It grows in disturbed, moist environments and meadows and has an unusual appearance as a pea, with narrow, flattened, grasslike leaves, no tendrils, and showy, pink flowers. Lathyrus nissolia has been characterized as potentially invasive in Victoria, Australia. In North America, it has been reported from Oregon and Washington and California. In California it was found for the first time outside of cultivation in 2013 in a meadow restoration site near Willets, Mendicino County. Its identity was confirmed in 2021 and it is now established across several acres. This plant is fast growing and can overtop other meadow vegetation, reaching a maximum height of up 0.4 - 0.9m by late spring. In California, Lathyrus nissolia may be threatening one or more sensitive wet meadow plant species, including North coast semaphoregrass, Pleuropogon hooverianus. Seeds are known to be toxic to livestock when ingested. There is good evidence to suspect that Lathyrus nissolia has expanded its distribution parts of Europe where it was previously not reported. Nonetheless, this evaluation classifies L. nissolia as a low risk for California, primarily because concrete evidence for its invasiveness in similar climates and its mode of dispersal are lacking.

Climate Matching Map

Climate Matching Map PDF

Attachment	Size
ClimateMatch_CA_Lathyrus_nissolia.pdf (1.11 MB)	1.11 MB

1. Question 1

Yes or No

Yes

Points

1

Confidence

Very High

Answer / Justification

Lathyrus nissolia is native to parts of Europe, northern Africa, and the Near East. It has become naturalized in Victoria (Australia), New Zealand, Tasmania, California and parts of Europe where it is presumed not to be native. CABI (2011) reports it as being introduced in Ireland, Poland, Sweden, and Australia. It has also been recorded in Washington State and Oregon, though its status there is unclear. A population previously reported as naturalized in Oregon appears to no longer exist (Giblin 2018), however it was recently reported from a new location in the state (iNaturalist). The earliest known record in California is from 2003 from a garden in Santa Rosa, Sonoma County. This record is discounted as an isolated garden escape. In 2013, L. nissolia was found in a restoration site near Willits (Mendocino Co., CA; Geri Hulse-Stephens, pers. comm.) where a population has been persisting and expanding locally since then. Its taxonomic identity was confirmed in 2021 by multiple herbaria (UC Davis, Berkeley, CDFA).

Reference(s)

Griese, D. 1989. “Occurrence and Phytosociological Behaviour of the Grass-Vetchling Lathyrus Nissolia L. In the Town Area of Wolfsburg (Southeastern Lower Saxony)”. Brauschw. Naturkdl. Schr. 3: 355-60.

Global Biodiversity Information Facility (GBIF),. 2022. “GBIF Backbone Taxonomy. Checklist Dataset for Lathyrus Nissolia Accessed via GBIF.Org on 2022-12-03”. https://www.gbif.org/species/5356542.

“Search Results for Lathyrus Nissolia, Accessed 12 3 2022”. 2022. https://plants.usda.gov/home/plantProfile?symbol=LANI3.

State of Victoria,. 2020. “Victoria Resources Online - Grass Vetchling (Lathyrus Nissolia)”. State of Victoria (Agriculture Victoria). https://vro.agriculture.vic.gov.au/dpi/vro/vrosite.nsf/pages/weeds_grass-vetchling.

Anonymous,. 2022. “Calflora - Lathyrus Nissolia”. https://www.calflora.org/app/taxon?crn=13677.

Giblin, D E. 2018. “Lathyrus L”. In , 2nd edition, 164-67. Seattle, WA: University of Washington Press and Burke Museum.

2022. “Search Results for Lathyrus Nissolia in California, Accessed 3 Dec 2022”. https://www.inaturalist.org/observations?place_id=14\&subview=map\&taxon_id=62017.

2. Question 2

Yes or No

Yes

Points

2

Confidence

Very High

Answer / Justification

Lathyrus nissolia has become naturalized and is spreading locally in California (Calflora 2022; Hulse-Stephens et al., personal communication). It is apparently also naturalized in Tazmania, where climate matches that of California. In Victoria, Australia, L. nissolia has been identified as a locally problematic invasive plant, though the exact climate where it occurs does not match that of California. In California, Lathyrus nissolia is known to have two self-sustaining populations: one near Willits (Mendocino Co.) at a restoration site and one near Healdsburg (Sonoma Co.) at a trailhead. In Oregon, where climate matches, L. nissolia was previously naturalized. Currently, L. nissolia is not listed in the Jepson Manual for California.

Reference(s)

Global Biodiversity Information Facility (GBIF),. 2022. “GBIF Backbone Taxonomy. Checklist Dataset for Lathyrus Nissolia Accessed via GBIF.Org on 2022-12-03”. https://www.gbif.org/species/5356542.

State of Victoria,. 2020. “Victoria Resources Online - Grass Vetchling (Lathyrus Nissolia)”. State of Victoria (Agriculture Victoria). https://vro.agriculture.vic.gov.au/dpi/vro/vrosite.nsf/pages/weeds_grass-vetchling.

Anonymous,. 2022. “Calflora - Lathyrus Nissolia”. https://www.calflora.org/app/taxon?crn=13677.

2022. “Search Results for Lathyrus Nissolia in California, Accessed 3 Dec 2022”. https://www.inaturalist.org/observations?place_id=14\&subview=map\&taxon_id=62017.

Giblin, D E. 2018. “Lathyrus L”. In , 2nd edition, 164-67. Seattle, WA: University of Washington Press and Burke Museum.

“Invasive Species Databases: Lathyrus Nissolia. Accessed 22 Feb 2023”. 2011.

3. Question 3

Yes or No

No

Points

0

Confidence

Low

Answer / Justification

Lathyrus nissolia has been introduced into several parts of the world, but it has not yet been listed as a highly problematic species in any of them. The Province of Victoria, Australia, has assessed and listed L. nissolia as an invasive plant on its website, primarily due to its poisonous seeds that present potential threat to rangelands. The population recently confirmed in Mendocino County, California appears to be threatening local native meadow species (Hulse-Stephens et al., pers. comm.). A "B" rating has recently been proposed by the California Department of Food and Agriculture for Lathyrus nissolia, based on its potential impacts to rangeland and the listed North coast semaphoregrass (Pleuropogon hooverianus), however this rating refers to risk, not actual invasiveness. It is not currently listed as "invasive" anywhere in the Global Compendium of Weeds (Randall, 2017).

Reference(s)

“California Pest Rating Proposal for Lathyrus Nissolia L. Grass Vetchling, Grass Pea”. 2022, 1-7.

State of Victoria,. 2020. “Victoria Resources Online - Grass Vetchling (Lathyrus Nissolia)”. State of Victoria (Agriculture Victoria). https://vro.agriculture.vic.gov.au/dpi/vro/vrosite.nsf/pages/weeds_grass-vetchling.

Randall, R. P. 2017. “A Global Compendium of Weeds. Third Edition”. Dept. of Agriculture and Food, Western Australia. https://www.researchgate.net/publication/313645439_A_Global_Compendium_of_Weeds_Third_Edition.

4. Question 4

Yes or No

No

Points

0

Confidence

Low

Answer / Justification

Lathyrus nissolia is listed as invasive on Agriculture Victoria's (Australia) website of invasive plants due to it's potential to spread based on suitable climate, its poisonous nature to livestock, especially horses, and its apparent lack of other local ecological benefit. However, the area that L. nissolia occurs is slightly beyond the climate match overlay for California.
In California, L. nissolia is posing a potential threat to North coast semephoregrass and other wet meadow species (G. Hulse-Stephens). However, data are still being gathered on this relationship. CDFA has proposed a "B" listing for the species, but it is based on future risk and not actual occurrence.

Reference(s)

“California Pest Rating Proposal for Lathyrus Nissolia L. Grass Vetchling, Grass Pea”. 2022, 1-7.

State of Victoria,. 2020. “Victoria Resources Online - Grass Vetchling (Lathyrus Nissolia)”. State of Victoria (Agriculture Victoria). https://vro.agriculture.vic.gov.au/dpi/vro/vrosite.nsf/pages/weeds_grass-vetchling.

5. Question 5

Yes or No

Yes

Points

1

Confidence

High

Answer / Justification

Lathyrus latifolius is listed as noxious in Oregon, which largely overlaps California in climate. There, it has been reported as becoming very dense and often "completely covering all other low-growing vegetation." It is also listed as invasive in Queensland, sections of which overlap in climate.

Reference(s)

Agriculture, Oregon Dept of. n.d. “Oregon Department of Agriculture ‘B’ Rated Weeds: Perennial Peavine”. https://www.oregon.gov/ODA/shared/Documents/Publications/Weeds/PerennialpeavineProfile.pdf.

States, Invasive Plant Atlas of the United. n.d. “Everlasting Peavine: Lathyrus Latifolia: Invasive Plant Atlas of the United States”. https://www.invasiveplantatlas.org/subject.html?sub=5912.

Government, Queensland. n.d. “Lathyrus Latifolius Fact Sheet from Environmental Weeds of Australia for Biosecurity Queensland Edition”. http://keyserver.lucidcentral.org/weeds/data/media/Html/lathyrus_latifolius.htm.

6. Question 6

Yes or No

No

Points

0

Confidence

Medium

Answer / Justification

Although Lathyrus nissolia's native and introduced range overlaps with that of California, it is common across a large section of western Europe as well as in parts of southern Russia where climate does not match (see Climate Match map).

Reference(s)

Global Biodiversity Information Facility (GBIF),. 2022. “GBIF Backbone Taxonomy. Checklist Dataset for Lathyrus Nissolia Accessed via GBIF.Org on 2022-12-03”. https://www.gbif.org/species/5356542.

7. Question 7

Yes or No

Yes

Points

1

Confidence

Medium

Answer / Justification

Observations by G. Hulse-Stephens, Mendocino Co. botanist, and by the author support the capacity for this plant to smother and overtop other wet meadow species. Hulse-Stephens counted 180 plants in a quarter 1m2 area, covering 85% of the area. Most plants were of a single stem, however others were found in the area to have multiple stems (counts up to six branches) with some evidence even of second season regrowth. Plants grew to to a height that overtopped other plants early in the season.
The tall growth form of this plant and other reports of its aggressive nature further support a "yes" for this answer (Griese 1989, Gilpin 2018, Lauber et al. 2018).

Reference(s)

Lauber, K., G. Wagner, and A. Gygax. 2018. Flora Helvetica - Illustrierte Flora Der Schweiz. Haupt Verlag. http://www.flora-helvetica.ch.

Griese, D. 1989. “Occurrence and Phytosociological Behaviour of the Grass-Vetchling Lathyrus Nissolia L. In the Town Area of Wolfsburg (Southeastern Lower Saxony)”. Brauschw. Naturkdl. Schr. 3: 355-60.

Giblin, D E. 2018. “Lathyrus L”. In , 2nd edition, 164-67. Seattle, WA: University of Washington Press and Burke Museum.

8. Question 8

Yes or No

No

Points

0

Confidence

High

Answer / Justification

The growth habit and and ecological preference for moist meadow habitat make it unlikely that Lathyrus nissolia would contribute positively or negatively to fire frequency. The fine, linear structure of this plant (with few, narrow, grasslike leaves) further provide little fuel for any wildfire.

Reference(s)

Lauber, K., G. Wagner, and A. Gygax. 2018. Flora Helvetica - Illustrierte Flora Der Schweiz. Haupt Verlag. http://www.flora-helvetica.ch.

Griese, D. 1989. “Occurrence and Phytosociological Behaviour of the Grass-Vetchling Lathyrus Nissolia L. In the Town Area of Wolfsburg (Southeastern Lower Saxony)”. Brauschw. Naturkdl. Schr. 3: 355-60.

9. Question 9

Yes or No

Yes

Points

1

Confidence

High

Answer / Justification

The seeds of Lathyrus nissolia are poisonous to mammals, including livestock, according to USDA GRIN.

Reference(s)

“Germplasm Resources Information Network (GRIN Taxonomy) for Lathyrus Nissolia Accessed 3 Dec 2022”. n.d. https://npgsweb.ars-grin.gov/gringlobal/taxon/taxonomydetail?id=21593.

10. Question 10

Yes or No

No

Points

0

Confidence

Medium

Answer / Justification

Due to the linear and vertical growth habit of Lathyrus nissolia and its annual nature, there is little reason to think that it could create impenetrable thickets, especially in the moist areas where it grows.

Reference(s)

Lauber, K., G. Wagner, and A. Gygax. 2018. Flora Helvetica - Illustrierte Flora Der Schweiz. Haupt Verlag. http://www.flora-helvetica.ch.

11. Question 11

Yes or No

No

Points

0

Confidence

Very High

Answer / Justification

Lathyrus nissolia is described by multiple sources as an annual plant, which then by definition would not reproduce vegetatively. There is some evidence from Mendocino populations that this species occasionally grows as a short-lived perennial or biennial (Hulse-Stephen and Burger, personal observations).

Reference(s)

Lauber, K., G. Wagner, and A. Gygax. 2018. Flora Helvetica - Illustrierte Flora Der Schweiz. Haupt Verlag. http://www.flora-helvetica.ch.

“Germplasm Resources Information Network (GRIN Taxonomy) for Lathyrus Nissolia Accessed 3 Dec 2022”. n.d. https://npgsweb.ars-grin.gov/gringlobal/taxon/taxonomydetail?id=21593.

State of Victoria,. 2020. “Victoria Resources Online - Grass Vetchling (Lathyrus Nissolia)”. State of Victoria (Agriculture Victoria). https://vro.agriculture.vic.gov.au/dpi/vro/vrosite.nsf/pages/weeds_grass-vetchling.

12. Question 12

Yes or No

No

Points

0

Confidence

Very High

Answer / Justification

Lathyrus nissolia is generally an annual plant that does not spread vegetatively.

Reference(s)

Lauber, K., G. Wagner, and A. Gygax. 2018. Flora Helvetica - Illustrierte Flora Der Schweiz. Haupt Verlag. http://www.flora-helvetica.ch.

“Germplasm Resources Information Network (GRIN Taxonomy) for Lathyrus Nissolia Accessed 3 Dec 2022”. n.d. https://npgsweb.ars-grin.gov/gringlobal/taxon/taxonomydetail?id=21593.

State of Victoria,. 2020. “Victoria Resources Online - Grass Vetchling (Lathyrus Nissolia)”. State of Victoria (Agriculture Victoria). https://vro.agriculture.vic.gov.au/dpi/vro/vrosite.nsf/pages/weeds_grass-vetchling.

13. Question 13

Yes or No

Yes

Points

1

Confidence

Very High

Answer / Justification

Multiple taxonomic references describe the flowers, pods, and seed that this species produces.

Reference(s)

Lauber, K., G. Wagner, and A. Gygax. 2018. Flora Helvetica - Illustrierte Flora Der Schweiz. Haupt Verlag. http://www.flora-helvetica.ch.

Cannon, J.F.M. 1964. “Infraspecific Variation in Lathyrus Nissolia L”. Watsonia 6: 28-35.

“Germplasm Resources Information Network (GRIN Taxonomy) for Lathyrus Nissolia Accessed 3 Dec 2022”. n.d. https://npgsweb.ars-grin.gov/gringlobal/taxon/taxonomydetail?id=21593.

14. Question 14

Yes or No

No

Points

0

Confidence

Medium

Answer / Justification

Sources differ in their estimates of seed production. Bramin et al., (2001) reports an average of 9.3 seeds per pod with few flowers per plant and further reports that flowers are entirely self-compatible. Hulse-Stephens counted seeds from multiple pods from the Mendocino Co. population and estimated between 13 - 17 seeds / pod with some plants containing 10 or more flowers. Regardless of the exact count, seed number is clearly well below 1000 even for the more prolifically seeding plant. Plants also had a 100g seed weight of this species is 7.55g according to Kew.

Reference(s)

No references cited.

15. Question 15

Yes or No

No

Points

0

Confidence

Very High

Answer / Justification

Lathyrus nissolia appears to have significant dormancy. Van Assche (2003) reported germination of less than 5% for seeds kept at 10C and no germination for seeds left at room temperature. Seeds germinated at up to 20% after burial for nearly two years and fluctuating cold temperatures. Alternatively, seeds germinate readily with scarification (Griese 1989). Van Assche et al. (2003) provided additional evidence that low germination was not due to low seed viability: 88% of seed buried for six months remained viable.

Reference(s)

Griese, D. 1989. “Occurrence and Phytosociological Behaviour of the Grass-Vetchling Lathyrus Nissolia L. In the Town Area of Wolfsburg (Southeastern Lower Saxony)”. Brauschw. Naturkdl. Schr. 3: 355-60.

Van Assche, J.A., K.L.A. Debucquoy, and W.A.F. Rommens. 2003. “Seasonal Cycles in the Germination Capacity of Buried Seeds of Some Leguminosae (Fabaceae)”. New Phytologist 158: 315-23.

16. Question 16

Yes or No

Yes

Points

1

Confidence

Very High

Answer / Justification

Cannon (1964) has reported that Lathyrus nissolia will grow from seed to maturity in four months.

Reference(s)

Cannon, J.F.M. 1964. “Infraspecific Variation in Lathyrus Nissolia L”. Watsonia 6: 28-35.

17. Question 17

Yes or No

No

Points

0

Confidence

Medium

Answer / Justification

Flowering appears to occur in late spring, after which plants senesce. The reported bloom period in Calflora is April - June.

Reference(s)

Anonymous,. 2022. “Calflora - Lathyrus Nissolia”. https://www.calflora.org/app/taxon?crn=13677.

18. Question 18

Yes or No

No

Points

0

Confidence

Low

Answer / Justification

I could find no evidence supporting long distance dispersal by mammals or birds.

Reference(s)

No references cited.

19. Question 19

Yes or No

No

Points

0

Confidence

Low

Answer / Justification

Nothing about the distribution or seed structure of Lathyrus nissolia suggests that it could be dispersed by wind or water: seeds are slightly flattened and approximately 3mm diameter with out any structures to aid with floatation.

Reference(s)

“Germplasm Resources Information Network (GRIN Taxonomy) for Lathyrus Nissolia Accessed 3 Dec 2022”. n.d. https://npgsweb.ars-grin.gov/gringlobal/taxon/taxonomydetail?id=21593.

20. Question 20

Yes or No

Yes

Points

1

Confidence

Low

Answer / Justification

The only likely means by which this species moved to new sites is through contaminated seed or equipment, but I could not find any documentation of movement. Seeds are 3mm in diameter, rounded, and flattened and could easily lodge into equipment or be carried with soil.

Reference(s)

“Germplasm Resources Information Network (GRIN Taxonomy) for Lathyrus Nissolia Accessed 3 Dec 2022”. n.d. https://npgsweb.ars-grin.gov/gringlobal/taxon/taxonomydetail?id=21593.

Evaluation Notes

Evaluator's note: This evaluation was difficult to conduct because of the general lack of information available on the species. Lathyrus nissolia may eventually be re-evaluated as a high risk once its impacts are better known.

Total PRE Score

PRE Score

9

Questions Answered

20

Screener Confidence (%)

72

PRE Score Legend

The PRE Score is calculated by adding the point totals for each (answered) question.

< 13 : Low Potential Risk
13 - 15 : Moderate Potential Risk
> 15 : High Potential Risk

Questions Answered Legend

It is important to answer at least 16 questions to consider a PRE Score as "valid".

≥ 16 : Valid (80% or more questions answered)
≤ 15 : Invalid (not enough questions answered)

Evaluation Credits and Citation

Screener: Jutta Burger

Below is a recommend citation when referencing this evaluation in other works:

Burger, Jutta. "Lathyrus nissolia -- California" Plant Risk Evaluator (PRE) published 2022-08-22 https://pretool.org/evaluations/1785

Please cite this evaluation. We need your support here!

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Evaluation Reviewers

	Elizabeth Brusati	reviewed on 2023-03-01
	Lynn Sweet	reviewed on 2022-12-23
	Alex Simmons	reviewed on 2022-12-21
	Scott Oneto	reviewed on 2022-12-19
	Marla Knight	reviewed on 2022-12-19
	Nicole Valentine	reviewed on 2022-12-16

Associated Project

2022 Western IPM Grant Project

"Expanding Continuity and Capacity in Invasive Plant Risk Assessments across Western States" is a continuation of the successful 2021 project titled "Building Continuity Across State Invasvie Plant Lists: Evaluating Invasive Risk of Horticultural Plants." Both 2021 and 2022's projects are funded by the Western Integrated Pest Management Center. Project partners for this year inclue the California Invasive Plant Council, PlantRight, The University of Arizona, Western Invasive Species Network, Pacific Northwest Invasive Species Council, the Yurok Tribe, and Nevada State Parks.

Associated Organizations, Agencies, and Institutions

California Invasive Plant Council (Cal-IPC)

PlantRight