Plant Assessment Form

Stipa miliacea var. miliacea

Synonyms: Piptatherum miliaceum; Agrostis miliacea L., Oryzopsis miliacea

Common Names: smilo grass; bamboo grass; milo; ricegrass; rice millet; millet mountain-rice; San Diego grass

Evaluated on: 8/2/04

List committee review date: 27/08/2004

Re-evaluation date:

Evaluator(s)

Jonathan C. Fox/ Research Associate
California Polytechnic State University, San Luis Obispo
591 Rosina Dr. Los Osos, CA 93402
(805)528-7091
anyplacewild@kcbx.net

List commitee members

John Randall
Cyntia Roye
Joe DiTomaso
Peter Warner
Alison Stanton
Jake Sigg

General Comments

Origin - Mediterranean
Removed second scientific name, Piptatherum miliaceum, and added it to the synonym line 3/28/17. Ramona Robison

Table 2. Criteria, Section, and Overall Scores

Overall Score? Limited
Alert Status? No Alert
Documentation? 2.5 out of 5
Score Documentation
1.1 ?Impact on abiotic ecosystem processes U Reviewed Scientific Publication
Impact?
Four-part score UBUC Total Score
C
1.2 ?Impact on plant community B. Moderate Observational
1.3 ?Impact on higher trophic levels U. Unknown
1.4 ?Impact on genetic integrity C. Minor/Low Other Published Material
2.1 ?Role of anthropogenic and natural disturbance in establishment B. Moderate Reviewed Scientific Publication
Invasiveness?
Total Points
14 Total Score B
2.2 ?Local rate of spread with no management A. Increases rapidly Observational
2.3 ?Recent trend in total area infested within state B. Increasing less rapidly Other Published Material
2.4 ?Innate reproductive potential
(see Worksheet A)
A. High Other Published Material
2.5 ?Potential for human-caused dispersal B. Moderate Other Published Material
2.6 ? Potential for natural long-distance dispersal C. Rare Other Published Material
2.7 ?Other regions invaded C. Already invaded Other Published Material
3.1 ?Ecological amplitude/Range
(see Worksheet C)
A. Widespread Other Published Material
Distribution?
Total Score B
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 Reviewed Scientific Publication
Identify ecosystem processes impacted:

Sources of information:

Question 1.2 Impact on plant community composition,
structure, and interactions?
B Observational
Identify type of impact or alteration:

Impacts community composition of riparian understory vegetation. Alters structure of grassland areas. Competes with and crowds out riparian understory vegetation. P. miliaceum is larger in stature than most native grasses. Grassland structure is altered by formation of small monospecific stands of P. miliaceum which creates a raised canopy.


Sources of information:

(1) Knapp, J.J. 2004. Personal observation during 2003 field surveys on Santa Catalina Island, CA. (310)510-1299, knappweed@catalinaisp.com


Question 1.3 Impact on higher trophic levels? U
Identify type of impact or alteration:

Sources of information:

Question 1.4 Impact on genetic integrity? C Other Published Material

Members of this genus have been known to hibridize with Achnatherum hymenoides (INDIAN RICEGRASS)(1). A. hymenoides and P. miliaceum have overlapping ranges in Southern Coastal California(2). A. hymenoides is also sold as a horticultural plant(2). Hybridization may occur in other areas of California with horticultural plantings of A. hymenoides and infestations of P. miliaceum.


Sources of information:

(1) Watson, L. and Dallwitz, M.J. (1992 onwards). Grass genera of the world: descriptions, illustrations, identification, and information retrieval; including synonyms, morphology, anatom, physiology, phytochemistry, cytology, classification, pathogens, world and local distribution, and references. http://biodiversity.uno.edu/delta/. Version: 18th August 1999.
(2) Hickman, J.C. ed.(1996). The Jepson Manual: higher plants of California. University of California Press, Ltd. London England. pg 1226 & 1283.


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

Typically found in areas with anthropogenic disturbance as well as natural disturbance. In semi-arid areas P. miliaceum may invade undisturbed areas. Literature for California describe habitats invaded as roadsides, fields and waste places(1). These are typically anthropogenic disturbances. P. miliaceum has also been described in riparian areas(1), on animal trails and near ground squirrel mounds(2). In East and South East Spain(native range), literature describes P. miliaceum in semi-arid grasslands(3). A study on the effects of arbuscular mycorrhizal on the development of plants colonizing a semi-arid area in Spain found P. miliaceum to have 100% survivability with or without the mycorrhizal treatment. Mycorrhizal innoculation showed no improvement in growth but significantly increased the number of seedlings germinated in the soil surrounding the mychorrhizal plant(3). This may facilitate invasion by P. miliaceum into undisturbed areas where these mycorrhizal relationships exist.


Sources of information:

(1) DiTomaso J., Healy E. Weeds of California and Other Western States. As yet unpublished. pg. 570
(2) Knapp, J.J. 2004. Personal observations during 2003 field surveys on Santa Catalina Island, CA. (310) 510-1299, knappweed@catalinaisp.com.
(3) Roldan-Fajardo, B.E. 1994. Effect of indigenous arbuscular mycorrhizal endophytes on the development of six wild plants colonizing a semi-arid area in south-east Spain. New Phytologist. 127(1): 115-121.


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

Extensive drainage segments exist on Santa Catalina Island that are still open to invasion, allowing P. miliaceum to increase within the Island (1). Neither floras for Santa Catalina Island list P. miliaceum, but by 2003, 2,854 populations were recorded (2).


Sources of information:

(1) Knapp, J.J. 2004. Personal observation during 203 field surveys on Santa Catalina Island, CA. (310)510-1299, knappweed@catalinaisp.com
(2) Knapp, J.J. 2004. Prioritized invasive plant management plan for the Santa Catalina Island Conservancy. Unpublished.


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

Listed by the Santa Barbara Botanic Garden as a species that should be eradicated when encountered on private property near wildlands (1). On Santa Catalina Island, P. miliaceum is one of the most wide spread species totalling 356 acres (2), but there has not been a concerted effort to reduce its abundance (3). Using information from Catalina Island because not much published information on this plant.


Sources of information:

(1)Santa Barbara Botanic Garden. No date. Worst invasive plants in Santa Barbara County: exotic species to eradicate if found on your property. http://www.santabarbarabotanicgarden.org/sections/visitor_info/visitor_level_3/visitor.
(2)Knapp, J.J. 2004. Prioritized invasive plant management plan for the Santa Catalina Island Conservancy. Unpublished.
1) Knapp, J.J. 2004. Personal observation during 203 field surveys on Santa Catalina Island, CA. (310)510-1299, knappweed@catalinaisp.com


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

Perennial (2) that reproduces by seed (1). Flowers April to September (2). P. miliaceum is both self and cross pollinated (3). Resporouts from underground rhizomes when cut (4).


Sources of information:

(1) DiTomaso J., Healy E. Weeds of California and Other Western States. As yet unpublished. pg. 570
(2) Wilken, D. and Hannah, L. 1998. Piptatherum miliaceum: Channel Islands National Park Service literature review. Unpublished.
(3) Watson, L. and Dallwitz, M.J. (1992 onwards). Grass genera of the world: descriptions, illustrations, identification, and information retrieval; including synonyms, morphology, anatom, physiology, phytochemistry, cytology, classification, pathogens, world and local distribution, and references. http://biodiversity.uno.edu/delta/. Version: 18th August 1999.
(4) Park, J., Allanson, A. and Tucker, P. No date. Rice millet (not a native grass) - Piptatherum miliaceum. Bushland weeds of South Australia. http://www.treesforlife.org.au/rogues/weeds/ricemillet.html.
(5) Observational List Committee, 8/2004.


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

P. miliaceum has been used in the revegetation of frequently burned chaparral (1). It is sometimes cultivated for livestock forage (2).


Sources of information:

(1) Wilken, D. and Hannah, L. 1998. Piptatherum miliaceum: Channel Islands National Park Service literature review. Unpublished.
(2) DiTomaso J., Healy E. Weeds of California and Other Western States. As yet unpublished. pg. 570


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

P. miliaceum reproduces by seed. Seeds of plant disperse to greater distances with water, soil movement, human activities, and possibly animals.


Sources of information:

(1) DiTomaso, JM, E Healy. Weeds of California and Other Western States. Not yet published.
(2) Observational, List Committee, 8/2004.


Question 2.7 Other regions invaded? C Other Published Material
Identify other regions:

P. miliaceum has been reported as waif in Great Britain and has become naturalized in California, western Nevada, and Australia (1). It can also be found in Arizona, Idaho, Utah, and a few northeastern states (2).


Sources of information:

(1) Wilken, D. and Hannah, L. 1998. Piptatherum miliaceum: Channel Islands National Park Service literature review. Unpublished.
(2) DiTomaso J., Healy E. Weeds of California and Other Western States. As yet unpublished. pg. 570


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

Introduced to California around the turn of the 19th entury from southern Europe(Los Angeles in 1896, Santa Barbara and Monrovia in 1916), and was reported mostly in urban waste areas in urban southern California by 1940. It has been reported from all four northern California Channel Islands and is now known from most southern California counties (1). According to the Jepson Manual (4) P. miliaceum can be found: North Coast, Central Valley, Central Coast, Central-western region, South Coast, to 300 m. P. miliaceum occurs in dry or moist sites in disturbed areas, roadsides and ditches (1). Some ecotypes may be found on acid soils (2) In California it appears to be increasing in riparian areas, ditches along roadsides, and canyons, especially in the southern region (3). On Santa Catalina Island 2,854 populations of smilo were GPS'd. These populations invadedriparian, grassland, coastalscrub/grassland, coastal scrub, chaparral, bare, dune, non-native and oak woodland habitats (5). Aluminum (Al) toxicity has been identified as one of the most important growth-limiting factors in acid soils. Some ecotypes of P. miliaceum have been found to be Al-tolerant (2)


Sources of information:

(1) Wilken, D. and Hannah, L. 1998. Piptatherum miliaceum: Channel Islands National Park Service literature review. Unpublished
(2) Zavas, T.; Symeonidis, L.; Karataglis, S. 1996. Responses to aluminum toxicity effects of two populations of Piptatherum miliaceum (L.) Cosson. Journal of Agronomy & Crop Science. 177(1): 25-32
(3) DiTomaso J., Healy E. Weeds of California and Other Western States. As yet unpublished. pg. 570
(4) Hickman, J.C. ed.(1993). The Jepson Manual: higher plants of California. University of California Press, Ltd. London England. pg 1226 & 1283.
(5) Knapp, J.J. 2004. Prioritized invasive plant management plan for the Santa Catalina Island Conservancy. Unpublished.


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

Occurs in less than 5% of any ecotype in CA.


Sources of information:

Observational, List Committee, 8/2004.


Worksheet A - Innate reproductive potential

Reaches reproductive maturity in 2 years or less Yes
Dense infestations produce >1,000 viable seed per square meter Yes
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 Unknown
Viable seed produced with both self-pollination and cross-pollination Yes
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 Yes
Total points: 6
Total unknowns: 1
Total score: A?

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
estuaries
DunescoastalD, < 5%
desert
interior
Scrub and Chaparralcoastal bluff scrub
coastal scrubD, < 5%
Sonoran desert scrub
Mojavean desert scrub (incl. Joshua tree woodland)
Great Basin scrub
chenopod scrub
montane dwarf scrub
Upper Sonoran subshrub scrub
chaparralD, < 5%
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)D, < 5%
Woodlandcismontane woodland
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): A
Distribution (highest score): D

Infested Jepson Regions

Click here for a map of Jepson regions