Polypremum procumbens L., Tetrachondraceae

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Present on Pacific Islands?  yes

Primarily a threat at high elevations?  no

Common name(s): [more details]

English: juniperleaf, rust weed, wireweed

Habit:  herb

Description:  "Low, spreading, glabrous herb with somewhat angled stems up to 12 cm long, readily branching at most nodes.  Leaves simple, opposite, blade linear, mostly 0.5-2.4 cm long, acuminate at the tip and base, surfaces glabrous, sometimes tinted red to orange, margins entire; subsessile.  Inflorescence of solitary, sessile, axillary flowers.  Corolla sympetalous, narrowly campanulate, 2.5-3 mm long, divided about halfway into 4 lobes; white.  Ovary superior; stamens 4, epipetalous.  Fruit an oval, laterally compressed, 2-lobed capsule 2-3 mm long, subtended by the 4 lanceolate, erect, slightly longer sepals.  Distinguishable by its small herbaceous habit, linear opposite leaves often red to orange in color, tiny, solitary, axillary, sessile white flowers, and small 2-lobed capsule"  (Whistler & Steele, 1999; p. 58).

Habitat/ecology:  In Hawai‘i, "reported as naturalized in Hawai‘i Volcanoes National Park, Hawai‘i" (Wagner et al., 1999; p. 850).  In the Marshall Islands, "a weed of open disturbed places, especially in sparse lawns with periodic mowing" (Kwajalein)  (Whistler & Steele, 1999; p. 58); in lawns and ruderal areas (Majuro) (Vander Velde, 2003; p.103).

Propagation:  Seed

Native range:  Tropical America (Whistler & Steele, 1999; p. 58).

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) Isabela Group	Isabela Island	introduced	Charles Darwin Foundation (2008)
Ecuador (Galápagos Islands) Isabela Group	Volcán Alcedo, Isabela Island	introduced invasive	Charles Darwin Foundation (2008)
Guam Guam Island	Guam Island	introduced	Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1979) (p. 211)
Guam Guam Island	Guam Island	introduced	Raulerson, L. (2006) (p. 55)
State of Hawaii Hawaiian Islands	Hawai‘i (Big) Island	introduced invasive	Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (p. 850)
Marshall Islands Ralik Chain	Enewetak (Ãnewetak, Eniwetok) Atoll	introduced	Fosberg, F. Raymond (1990) (p. 36)
Marshall Islands Ralik Chain	Kwajalein (Kuwajleen) Atoll	introduced invasive	Whistler, W. A./Steele, O. (1999) (p. 58) Vouchers cited: Herbst 8980, Herbst 9018, Herbst 9030, Herbst 9050, Whistler 11169, Whistler 11259
Marshall Islands Ratak Chain	Majuro (Mãjro) Atoll	introduced invasive	Vander Velde, Nancy (2003) (p. 103)
Marshall Islands Ratak Chain	Mili (Mile) Atoll	introduced invasive	Vander Velde, Nancy/Vander Velde, Brian (2010) (p. A17) Uncommon; in fields, including runway, Mili, perhaps Tokewa.
Marshall Islands Ratak Chain	Wotje (Wõjjã) Atoll	introduced	Vander Velde, Nancy/Vander Velde, Brian (2009) (p. 2) Voucher cited: Vander Velde 0514200925
Palau Palau (main island group)	Angaur Island	introduced	Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1979) (p. 211)
Palau Palau (main island group)	Angaur Island		Beleu National Museum (Republic of Palau. Koror.) (1970) (voucher ID: BNM 496) Taxon name on voucher: Polypremum procumbens L.
Palau Palau (main island group)	Angaur Island		Beleu National Museum (Republic of Palau. Koror.) (1977) (voucher ID: BNM 906) Taxon name on voucher: Polypremum procumbens L.

Additional information:
More photos at Missouri Plants.

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

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

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

References:

Beleu National Museum (Republic of Palau. Koror.). 1970. Voucher specimen #BNM496(Salsedo, Carl. A. 354).

Beleu National Museum (Republic of Palau. Koror.). 1977. Voucher specimen #BNM906(Canfield, J.E. 180).

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

Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce. 1979. A geographical checklist of the Micronesian dicotyledonae. Micronesica 15:1-295.

Fosberg, F. Raymond. 1990. A review of the natural history of the Marshall Islands. Atoll Research Bulletin No. 330. Smithsonian Institution, Washington. 100 pp.

Raulerson, L. 2006. Checklist of Plants of the Mariana Islands. University of Guam Herbarium Contribution 37:1-69. .

Vander Velde, Nancy. 2003. The vascular plants of Majuro Atoll, Republic of the Marshall Islands. Smithsonian Institution, Atoll Research Bulletin No. 503:1-141.

Vander Velde, Nancy/Vander Velde, Brian. 2009. Specimens from Likiep, Majuro, Wotje and Arno (unpublished checklist). 4 pp.

Vander Velde, Nancy/Vander Velde, Brian. 2010. Survey of Invasive Plant Species and Other Plants of Mili Atoll, Marshall Islands. USDA Forest Resource Management Grant Program. Unpublished report. 6 pp, plus tabulation of plants of Mili Atoll, 23 pp.

Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. 1999. Manual of the flowering plants of Hawaii. Revised edition. Bernice P. Bishop Museum special publication. University of Hawai‘i Press/Bishop Museum Press, Honolulu. 1919 pp. (two volumes).

Whistler, W. A./Steele, O. 1999. Botanical survey of the United States of America Kwajalein Atoll (USAKA) Islands. Prepared for Oak Ridge Institute for Science and Education and the U. S. Army Environmental Center. 111 pp.