Richardia scabra L., Rubiaceae

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Present on Pacific Islands?  yes

Primarily a threat at high elevations?  no

Risk assessment results:  Reject, score: 8 (Go to the risk assessment).

Other Latin names:  Richardsonia scabra (L.) A. St.-Hil.

Common name(s): [more details]

English: rough Mexican clover

Habit:  herb

Description:  "The root is a taproot and the stem is branched, erect, fleshy, very hairy and 20 to 50 centimeters tall.  The leaves are also pubescent and are sessile, opposite, entire, oblong or elliptical to lanceolate or ovate, 2 to 4 centimeters long and 1 to 1.5 centimeters wide.  The inflorescence is a white flower-head subtended by four leaf bracts, two longer than the others.  The flowers are perfect and occur in terminal clusters.  The calyx is a small whorl consisting of 5 to 6 pointed lobes.  The fruit is a capsule divided into 3 to 4 parts and produces flat, obovate seeds"  (Cardenas et al., 1972; p. 265).

"Richardia brasiliensis has mericarps that are adaxially broadly and openly concave with a slim median keel, whereas those of Richardia scabra are adaxially closed to a narrow groove or sulcus.  These 2 species are otherwise similar in morphology"  (Lorence et al., 1995; pp. 50-51).

Habitat/ecology:  "Annual herb common in cultivated fields, perennial crops, waste areas, roadsides and ditchbanks"  (Cardenas et al., 1972; p. 265).

Propagation:  Seed (Cardenas et al., 1972; p. 265).

Native range:  United States, Mexico, Central and South America (GRIN).

Presence:

Pacific
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
State of Hawaii Hawaiian Islands	Hawai‘i (Big) Island	introduced invasive	Pratt, Linda W./Bio, Leali‘i F. (2012) (p. 79) Voucher cited: L.W. Pratt 3556 (BISH)
State of Hawaii Hawaiian Islands	Kaua‘i Island	introduced invasive	Lorence, David H./Flynn, Timothy W./Wagner, Warren L. (1995) (pp. 50-51) Vouchers cited: M. Kiehn & T. Flynn MK-900920-1/1 (PTBG, US, WU), M. Kiehn & T.Flynn MK-900917-2/1 (PTBG, WU), T. Flynn 1245 (PTBG)
State of Hawaii Hawaiian Islands	Maui Island	introduced invasive	Oppenheimer, Hank L. (2003) (p. 23) West Maui. Voucher cited: Oppenheimer H100045 (BISH)
State of Hawaii Hawaiian Islands	Maui Island	introduced invasive	Imada, Clyde T./James, Shelly A./Kennedy, Barbara H. (2008) (p. 14) Vouchers cited: East Maui: W. L. Wagner & S. Mill 4739 (BISH), F. Starr & K. Martz 010726-3 (BISH). West Maui: H. Oppenheimer H30706 (BISH)
State of Hawaii Hawaiian Islands	Moloka‘i Island	introduced invasive	Imada, Clyde T./James, Shelly A./Kennedy, Barbara H. (2008) (p. 14) Voucher cited: Oppenheimer H40404 (BISH, PTBG)
State of Hawaii Hawaiian Islands	O‘ahu Island	introduced invasive	Imada, Clyde T./James, Shelly A./Kennedy, Barbara H. (2008) (p. 14) Voucher cited: C. Imada & L. Crago 2004-27 (BISH)

Pacific Rim
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
Australia Australia (continental)	Australia (continental)		Holm, Leroy/Pancho, Juan V./Herberger, James P./Plucknett, Donald L. (1979) (p. 309)
China China	Hong Kong	introduced invasive	Wu, Te-lin (2001) (p. 270) On grassland or in wasteland.
Colombia Colombia	Colombia (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2011)
Costa Rica Costa Rica	Costa Rica (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2011)
Ecuador (Mainland) Ecuador	Ecuador (Republic of) (continental)	native	U.S. Dept. Agr., Agr. Res. Serv. (2011)
El Salvador El Salvador	El Salvador (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2011)
Guatemala Guatemala	Guatemala (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2011)
Honduras Honduras	Honduras (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2011)
Japan Japan	Japan (country)	introduced	Mito, Toshikazu/Uesugi, Tetsuro (2004) (p. 187)
Mexico Mexico	Mexico (United Mexican States)	native	U.S. Dept. Agr., Agr. Res. Serv. (2011)
Nicaragua Nicaragua	Nicaragua (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2011)
Panama Panama	Panama (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2011)
Perú Perú	Perú (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2011)

Also reported from
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
United States (continental except west coast) United States (other states)	USA (Florida)	native	U.S. Dept. Agr., Agr. Res. Serv. (2011)

Additional information:
Fact sheet from the University of Florida Agricultural Extension

Additional online information about Richardia scabra is available from the Hawaiian Ecosystems at Risk project (HEAR).

Information about Richardia scabra as a weed (worldwide references) may be available from the Global Compendium of Weeds (GCW).

Taxonomic information about Richardia scabra may be available from the Germplasm Resources Information Network (GRIN).

References:

Holm, Leroy/Pancho, Juan V./Herberger, James P./Plucknett, Donald L. 1979. A geographical atlas of world weeds. John Wiley & Sons, New York. 391 pp.

Imada, Clyde T./James, Shelly A./Kennedy, Barbara H. 2008. New plant records from Herbarium Pacificum for 2007. In: Evenhuis, Neal L. and Eldredge, Lucias G., eds. Records of the Hawaii Biological Survey for 2007. Bishop Museum Occasional Papers 100:12-16.

Lorence, David H./Flynn, Timothy W./Wagner, Warren L. 1995. Contributions to the flora of Hawai‘i. III. New additions, range extensions, and rediscoveries of flowering plants. In: Evenhuis, Neal L. and Miller, Scott, E., eds. Records of the Hawaii Biological Survey for 1994. Part 1: Articles. Bishop Museum Occasional Papers. 41:19-58.

Mito, Toshikazu/Uesugi, Tetsuro. 2004. Invasive alien species in Japan: the status quo and the new regulation for prevention of their adverse effects. Global Environmental Research 8(2)/2004: 171-191.

Oppenheimer, Hank L. 2003. New plant records from Maui and Hawai‘i Counties. In: Evenhuis, Neal L. and Eldredge, Lucius G., eds. Records of the Hawaii Biological Survey for 2001-2002. Part 1: Articles. Bishop Museum Occasional Papers. 73:3-30.

Pratt, Linda W./Bio, Leali‘i F. 2012. New plant records from Hawai‘i Island. In: Evenhuis, Neal L. and Eldredge, Lucius G., eds. Records of the Hawaii Biological Survey for 2011. Part II: Plants. Bishop Museum Occasional Papers. 113:75-80.

U. S. Government. 2011. Integrated Taxonomic Information System (ITIS) (on-line resource).

U.S. Dept. Agr., Agr. Res. Serv. 2011. National Genetic Resources Program. Germplasm Resources Information Network (GRIN). Online searchable database.

Wu, Te-lin. 2001. Check List of Hong Kong Plants. Hong Kong Herbarium and the South China Institute of Botany. Agriculture, Fisheries and Conservation Department Bulletin 1 (revised). 384 pp.