Porophyllum ruderale (Jacq.) Cass., Asteraceae

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Present on Pacific Islands?  yes

Primarily a threat at high elevations?  no

Risk assessment results:  High risk; score: 8 (Hawaii-Pacific Weed Risk Assessment for Porophyllum ruderale)

Other Latin names:  Kleinia ruderalis (Jacq.) Cass.; Porophyllum ellipticum (Jacq.) Cass.; Porophyllum macrocephalum DC.; Porophyllum ruderale M. Gómez

Common name(s): [more details]

Spanish: yerba porosa

Habit:  herb

Description:  "Stout, malodorous, tap-rooted, annual herbs; stems erect, 0.15-1.5 m tall, often much branched above, terete, striate, leafy, green or purplish, often glaucous, glabrous. Leaves opposite or alternate, slender-petiolate, simple, ovate, elliptical or obovate, cuneate, crisped-undulate or crenate, pinnately veined, glabrous, often glaucous, punctate with conspicuous, crescent-shaped or oblong marginal oil glands and sometimes with additional scattered glands. Inflorescence corymbi- form; peduncles 3-5 cm long, terminating leafy branches, glabrous, often glaucous. Heads discoid; involucres cylindric at anthesis, 13-22 mm long, 5-10 mm diam., the bracts 5, linear-oblong, acute, flat, glabrous, glaucous, streaked with elongate glands, the margin thin, hyaline; florets 30-60, the corollas greenish to purplish, 10-13 mm long, sparsely puberulent, the tube slender, 8-10 mm long, the throat short, abruptly expanded, equally Slobed, the anthers 1.5-2 mm long with short acute to acuminate, rhombic appendages, the style branches long, slender, curved. Achenes cylindric, black or brownish, densely hispidulous, 7-12 mm long; carpopodium conspicuous; pappus of many slender, scabrid, tawny bristles 7-11 mm long." (Flora de Panama)

"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 of disturbed soils [305]. Brushy rocky slopes or plains, most often in sandy soil, frequently on sandbars along streams, at elevations of 200 - 1,200 metres [331]. Ephemerally wet sites in desert mountains; 1,000 - 1,500 metres [270]." (Useful Tropical Plants)

In cultivation: "It is usually found in very freely draining soils, often in semi-arid regions where it grows after rains. Requires a sunny position, succeeding in a range of soil types so long as they are well-drained." (Useful Tropical Plants)

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

Propagation:  Cultivation: "Seed - sow in situ" (Useful Tropical Plants)

Native range:  The native range of Porophyllum ruderale (Jacq.) Cass. (Asteraceae) includes Mexico; Central America; South America; and the U.S. states of Arizona, New Mexico, and Texas. (For more details, see GRIN.)

Impacts and invaded habitats:  "...the subspecies macrocephalum is often found as a weed of waste and disturbed ground in its native habitat. It was introduced into the Galapagos as a food, where it has escaped from cultivation and is now classed as an invasive weed [305]." (Useful Tropical Plants)

"A weed of disturbed soils [305]. Brushy rocky slopes or plains, most often in sandy soil, frequently on sandbars along streams, at elevations of 200 - 1,200 metres [331]. Ephemerally wet sites in desert mountains; 1,000 - 1,500 metres [270]." (Useful Tropical Plants)

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

If you know of other invaded habitats or impacts of Porophyllum ruderale, please let us know.

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) Galápagos Islands	Galápagos Islands	invasive	Randall, R. P. (2017) (p. 2743)

Pacific Rim
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
Asia Asia	Asia (southeast)		Randall, R. P. (2017) (p. 2743)
Asia Asia	Asia (southern)		Randall, R. P. (2017) (p. 2743)
Australia Australia	Australia		Randall, R. P. (2017) (p. 2743)
Indonesia Indonesia	Indonesia (Republic of)		Randall, R. P. (2017) (p. 2743)
Malaysia Malaysia	Malaysia (country of)		Randall, R. P. (2017) (p. 2743)
Mexico Mexico	Mexico (United Mexican States)		Randall, R. P. (2017) (p. 2743)
Singapore Singapore	Singapore (Republic of)		Randall, R. P. (2017) (p. 2743)
South America (Pacific rim) South America (Pacific rim)	Chile (Republic of)		Randall, R. P. (2017) (p. 2743)
South America (Pacific rim) South America (Pacific rim)	Colombia		JSTOR Global Plants (year unknown) herbarium specimen at this URL
South America (Pacific rim) South America (Pacific rim)	Ecuador		Randall, R. P. (2017) (p. 2743)
South America (Pacific rim) South America (Pacific rim)	Perú (Republic of)		Randall, R. P. (2017) (p. 2743)

Also reported from
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
Caribbean Islands Caribbean Islands	Cuba		JSTOR Global Plants (year unknown) herbarium specimen at this URL
Caribbean Islands Caribbean Islands	Guadeloupe		JSTOR Global Plants (year unknown) herbarium specimen at this URL
Caribbean Islands Caribbean Islands	Puerto Rico		JSTOR Global Plants (year unknown) herbarium specimen at this URL
Caribbean Islands Caribbean Islands	Trinidad		Randall, R. P. (2017) (p. 2743)
Caribbean Islands Caribbean Islands	West Indies		Woodson Jr., Robert E./Schery, Robert W. (1980) "extending from the southwestern United States and the West Indies south to northern Argentina."
Jamaica Jamaica	Jamaica (country)		JSTOR Global Plants (year unknown) herbarium specimen at this URL
South America South America	Argentina		JSTOR Global Plants (year unknown) herbarium specimen at this URL
South America South America	South America		Randall, R. P. (2017) (p. 2743)
South America South America	South America		Woodson Jr., Robert E./Schery, Robert W. (1980) "extending from the southwestern United States and the West Indies south to northern Argentina."
South America (non-Pacific rim) South America (non-Pacific rim)	Brazil		Randall, R. P. (2017) (p. 2743)
South America (non-Pacific rim) South America (non-Pacific rim)	Brazil		JSTOR Global Plants (year unknown) herbarium specimen at this URL
South America (non-Pacific rim) South America (non-Pacific rim)	Guyana		JSTOR Global Plants (year unknown) herbarium specimen at this URL
South America (non-Pacific rim) South America (non-Pacific rim)	Paraguay		JSTOR Global Plants (year unknown) herbarium specimen at this URL
United States of America United States	United States (southwestern)		Woodson Jr., Robert E./Schery, Robert W. (1980) "extending from the southwestern United States and the West Indies south to northern Argentina."
United States (continental except west coast) United States (other states)	United States (other states)		Flora of North America (year unknown) see ref for (state) details. Distribution map. Onl

Control:  If you know of control methods for Porophyllum ruderale, please let us know.