Porophyllum ruderale subsp. macrocephalum (DC.) R. R. Johnson, Asteraceae

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Present on Pacific Islands?  yes

Primarily a threat at high elevations?  no

Other Latin names:  Porophyllum macrocephalum DC.

Common name(s): [more details]

English: poreleaf

Spanish: ruda gallinazo, yerba porosa

Habit:  herb

Description:  "Erect, subsimple to freely branched, malodorous annual, 2-10 dm tall, conspicuously blue-glaucous throughout; blades thin, narrowly to more often broadly elliptic, obtuse or rounded to somewhat acute at both ends, broadly and shallowly undulate-toothed, commonly with prominent oil gland 1-1.5 mm long associated with each sinus, mostly 1.5-4 cm long, 0.5-2.5 cm wide on well-developed, slender petiole often nearly or fully as long; heads erect, terminating the branches, on clavate peduncles mostly 3-10 cm long; involucre cylindric at anthesis, its 5 or 6 bracts narrow and elongate, mostly 17-21 mm long, persistent and becoming reflexed in age; disk dark, only about 6-7 mm wide at anthesis; flowers more or less numerous, from about 21 to more than 65; corolla about 1 cm long, the very slender, pale tube many times longer than the very short, purple throat; corolla about 1 cm long, the very slender, pale tube many times longer than the very short, purple throat; corolla lobes about 1 mm long or a bit more, equaling or longer than throat, purple or greenish; achenes 9-13 mm long, with prominent, smooth, shining, pale, callous base; pappus sordid or brownish, nearly or fully 1 cm long"  (Wiggins & Porter, 1971; pp. 349-351).

Habitat/ecology:  "A weed in disturbed soil" (Wiggins & Porter, 1971; pp. 349-351). Arid lowlands in the Galápagos Islands (McMullen, 1999; p. 217).

Propagation:  Seed

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
Ecuador (Galápagos Islands) Española Group	Española Island	introduced invasive	Charles Darwin Foundation (2008)
Ecuador (Galápagos Islands) Española Group	Gardner por Española Islet, Española Island	introduced invasive	Charles Darwin Foundation (2008)
Ecuador (Galápagos Islands) Española Group	Oeste Islet, Española Island	introduced invasive	Charles Darwin Foundation (2008)
Ecuador (Galápagos Islands) Floreana Group	Floreana Island	introduced invasive	Charles Darwin Foundation (2008)
Ecuador (Galápagos Islands) Isabela Group	Isabela Island	introduced invasive	Charles Darwin Foundation (2008)
Ecuador (Galápagos Islands) Isabela Group	Volcán Alcedo, Isabela Island	introduced invasive	Charles Darwin Foundation (2008)
Ecuador (Galápagos Islands) Isabela Group	Volcán Darwin, Isabela Island	introduced invasive	Charles Darwin Foundation (2008)
Ecuador (Galápagos Islands) Isabela Group	Volcán Sierra Negra, Isabela Island	introduced invasive	Charles Darwin Foundation (2008) ssp. macrocephalum
Ecuador (Galápagos Islands) Isabela Group	Volcán Wolf, Isabela Island	introduced invasive	Charles Darwin Foundation (2008)
Ecuador (Galápagos Islands) Pinta Group	Pinta Island	introduced invasive	Charles Darwin Foundation (2008)
Ecuador (Galápagos Islands) Pinzón Group	Pinzón Island	introduced invasive	Charles Darwin Foundation (2008)
Ecuador (Galápagos Islands) San Cristóbal Group	San Cristóbal Island	introduced invasive	Charles Darwin Foundation (2008)
Ecuador (Galápagos Islands) Santa Cruz Group	Daphne Mayor Island, Santa Cruz Island	introduced invasive	Charles Darwin Foundation (2008)
Ecuador (Galápagos Islands) Santa Cruz Group	Edeén Island	introduced invasive	Charles Darwin Foundation (2008)
Ecuador (Galápagos Islands) Santa Cruz Group	Santa Cruz Island	introduced invasive	Charles Darwin Foundation (2008)
Ecuador (Galápagos Islands) Santa Cruz Group	Seymour Norte Island	introduced invasive	Charles Darwin Foundation (2008)
Ecuador (Galápagos Islands) Santiago Group	Rábida Island	introduced invasive	Charles Darwin Foundation (2008)
Ecuador (Galápagos Islands) Santiago Group	Santiago Island	introduced invasive	Charles Darwin Foundation (2008)

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) Including Galapagos.
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)
Mexico Mexico	Mexico (United Mexican States)	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)
Singapore Singapore	Singapore (Republic of)	introduced invasive	Chong, Kwek Yan/Tan, Hugh T. W./Corlett, Richard T. (2009) (p. 72) Naturalised

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)	United States (other states)	native	U.S. Dept. Agr., Agr. Res. Serv. (2011)

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

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

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

References:

Charles Darwin Foundation. 2008. Database inventory of introduced plant species in the rural and urban zones of Galapagos. Charles Darwin Foundation, Galapagos, Ecuador.

Charles Darwin Research Station. 2005. CDRS Herbarium records.

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.

McMullen, C. K. 1999. Flowering plants of the Galápagos. Comstock Pub. Assoc., Ithaca, N.Y. 370 p.

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