Dorstenia contrajerva L., Moraceae

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Present on Pacific Islands?  yes

Primarily a threat at high elevations?  no

Risk assessment results:  High risk, score: 9 (Go to the risk assessment)

Common name(s): [more details]

English: snakewort, tusilla

French: herbe aux serpents, herbe-chapeau, racine de charchis

Spanish: cabalhau, cambahan, contaúl, contra de cobra, contrahierba, contrayerba, hierba de loro, hierba de sapo, mano de león, xcambalhan

Habit:  herb

Description: 

Genus:  "Perennial herbs with milky sap, with rhizomes, acaulescent or with somewhat elongate stems; leaves very variable, usually long-petiolate, mostly membranaceous, entire, dentate, angulate, or pinnate-lobate; flowers minute, monoecious, densely crowded on a usually large, explanate, commonly saucer-like, entire or angulate or lobate receptacle, the receptacles axillary, long-pedunculate, the flowers of both sexes numerous and intermixed, the pistillate flowers usually surrounded each by 3-4 staminate ones, the bracts minute and inconspicuous; perianths commonly connate with the receptacle, their margins sometimes obscurely bilobate or bidentate; stamens 2, rarely 1 or 3, the filaments at first inflexed, finally porrect and exserted; ovary included, the style excentric or almost lateral, exserted, 2-fid, the short branches subulate; fruits very small, finally protruded from the pits of the receptacle, the exocarp fleshy, the endocarp crustaceous; testa of the seed thin-membranaceous; endosperm none; cotyledons subequal, embracing the ascending radicle"  (Standley & Steyermark, 1946; p. 27).

Species:  "Plants acaulescent or nearly so, the stems, if any, very short; leaves often very numerous and crowded, long-petiolate, deeply and pinnately or almost palmately lobate, sparsely scabrous or puberulent, usually somewhat rough to the touch, the lobes acute to acuminate, narrow or broad; receptacles on long slender peduncles, quadrangular or deeply and irregularly lobate, accrescent in age and 2-5 cm. wide, scaberulous beneath"  (Standley & Steyermark, 1946; p. 27).

Habitat/ecology:  In Guatemala (native), "moist forest or thickets, ascending from sea level to about 1,800 meters"  (Standley & Steyermark, 1946; p. 27).  In Florida (U.S.), "moist, disturbed sites; 0-20 m"  (Flora of North America online).

Propagation:  Seeds, explosively expelled  (Flora of North America online).

Native range:  Mexico through Central America and the Caribbean Islands to northern 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	O‘ahu Island		National Tropical Botanical Garden (U.S.A. Hawaii. Kalaheo.) (1999) (voucher ID: PTBG 28338) Taxon name on voucher: Dorstenia contrajerva L.
Japan (offshore islands) Bonin (Ogasawara) Islands	Bonin (Ogasawara) Islands	introduced	Toyoda, Takeshi (2003) (p. 464)
Japan (offshore islands) Bonin (Ogasawara) Islands	Bonin (Ogasawara) Islands	introduced	Kato, Hidetoshi (2007)

Pacific Rim
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
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) Guayas, Manabi
El Salvador El Salvador	El Salvador (Republic of)	native	Standley, Paul C./Steyermark, Julian A. (1946) (pp. 28-29)
Guatemala Guatemala	Guatemala (Republic of)	native	Standley, Paul C./Steyermark, Julian A. (1946) (pp. 28-29)
Honduras Honduras	Honduras (Republic of)	native	Standley, Paul C./Steyermark, Julian A. (1946) (pp. 28-29)
Mexico Mexico	Mexico (United Mexican States)	native	Standley, Paul C./Steyermark, Julian A. (1946) (pp. 28-29)
Nicaragua Nicaragua	Nicaragua (Republic of)	native	Standley, Paul C./Steyermark, Julian A. (1946) (pp. 28-29)
Panama Panama	Panama (Republic of)	native	Standley, Paul C./Steyermark, Julian A. (1946) (pp. 28-29)
Perú Perú	Perú (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2011) San Martin
Singapore Singapore	Singapore (Republic of)	introduced cultivated	Chong, Kwek Yan/Tan, Hugh T. W./Corlett, Richard T. (2009)

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., Nat. Res. Cons. Serv. (2011)

Additional information:
Additional online information about Dorstenia contrajerva is available from the Hawaiian Ecosystems at Risk project (HEAR).

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

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

References:

Chong, Kwek Yan/Tan, Hugh T. W./Corlett, Richard T. 2009. A checklist of the total vascular plant flora of Singapore: native, naturalised and cultivated species. Raffles Museum of Biodiversity Research, National University of Singapore. 273 pp.

Kato, Hidetoshi. 2007. Herbarium records of Makino Herbarium, Tokyo Metropolitan University. Personal communication.

National Tropical Botanical Garden (U.S.A. Hawaii. Kalaheo.). 1999. Voucher specimen #PTBG28338(Flynn, Tim 6519).

Standley, Paul C./Steyermark, Julian A. 1946. Flora of Guatemala. Fieldiana: Botany. Vol. 24, Part IV. Chicago Natural History Museum.

Toyoda, Takeshi. 2003. Flora of the Bonin Islands. Aboc & Co. 522 pp.

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.

U.S. Dept. Agr., Nat. Res. Cons. Serv. 2011. The PLANTS Database. National Plant Data Center, Baton Rouge, LA 70874-4490 USA.