Pacific Island Ecosystems at Risk (PIER)

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Spermacoce confusa
Rendle, Rubiaceae
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Present on Pacific Islands?  yes

Primarily a threat at high elevations?  no

Common name(s): [more details]

English: iron-grass, river false buttonweed

Spanish: hierba de Santa Clara, taulmil, yerba de hierro

Habit:  herb

Description:  "Annual herbs or subshrubs to 80 cm tall, with few or many branches, leafy stems 0.5-2.5 mm thick, with 4 prominent longitudinal ridges and with scabrid hairs along the ridges; stipule sheath ca. 1 mm long, glabrous. Leaves usually opposite and subsessile, petioles 0-3 (-6) mm long; leaf blades 2-6 cm long, 2-10 (-13) mm broad, lanceolate to oblanceolate or linear-lanceolate, apex acute to acuminate, base narrowed, with minute (0.1-0.2) mm) scabridulous hairs above, glabrous beneath, 2 veins 2-3/side, usually impressed above. Inflorescences small and axillary, few-flowered, ca. 4-6 mm long, of 6-15 flowers, the flowers sessile or subsessile. Flowers with hypanthium and calyx tube 1-1.5 mm long, calyx lobes 4, 0.4-1 mm long, triangular-lanceolate to linear-lanceolate, conspicuously ciliolate along the edges; corolla white, rose, lavender, or blue, tube ca. 1.5 mm long and 1 mm diameter, lobes 0.5-1 mm long, 0.4-0.5 mm broad, ovate-oblong, obtuse at the apex, minutely puberulent distally; filaments ca. 0.3 mm long. Fruits 1.5-3 mm long, obovoid to ellipsoid or subglobose, with short ascending hispidulous hairs to 0.5 mm long, with persisting calyx lobes 0.5-1 mm long; seeds 1.1-2 mm long, 0.5-1 mm broad, ellipsoid-oblong to obovoid-ellipsoid, bluntly rounded at both ends, yellowish to dark brown, lustrous, with minute shallow pits (x40), sinus less than 1/3 the width of the seed and constricted in the middle."

"Spermacoce confusa is recognized by the very narrow scabrous leaves, small compact inflorescences, and the asymmetric unevenly setose capsule that breaks into two parts, with one failing to open" (Berger, 1993; pp. 315-316).

Habitat/ecology:  "Plants of open weedy sites, from near sea level to 1000 m elevation (to 1600 m in Guatemala" (Berger, 1993; pp. 315-316). "In open places, along trails and roadsides, in fields and along fence rows, generally distributed in tropical America as a weed" (Wiggins & Porter, 1971; pp. 439-440).

Propagation:  Seed

Native range:  Mexico through Central America and the West Indies into South America (Berger, 1993; pp. 315-316).

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)
Floreana Group
Floreana Island introduced
invasive
Charles Darwin Foundation (2008)
Niue
Niue
Niue Island introduced
invasive
Space, James C./Flynn, Tim (2000) (p. Voucher)
Voucher: Flynn 6689 (PTBG, NIUE)
Niue
Niue
Niue Island   National Tropical Botanical Garden (U.S.A. Hawaii. Kalaheo.) (2000) (voucher ID: PTBG 30190)
Taxon name on voucher: Spermacoce confusa Rendle
Niue
Niue
Niue Island   National Tropical Botanical Garden (U.S.A. Hawaii. Kalaheo.) (1997) (voucher ID: PTBG 43028)
Taxon name on voucher: Spermacoce confusa Rendle
Pacific Rim
Country/Terr./St. &
Island group
Location Cited status &
Cited as invasive &
Cited as cultivated &
Cited as aboriginal introduction?
Reference &
Comments
Central America
Central America (Pacific rim)
El Salvador (Republic of) native
U.S. Dept. Agr., Agr. Res. Serv. (2013)
Central America
Central America (Pacific rim)
Guatemala (Republic of) native
U.S. Dept. Agr., Agr. Res. Serv. (2013)
Central America
Central America (Pacific rim)
Nicaragua (Republic of) native
U.S. Dept. Agr., Agr. Res. Serv. (2013)
Central America
Central America (Pacific rim)
Panama (Republic of) native
U.S. Dept. Agr., Agr. Res. Serv. (2013)
Mexico
Mexico
Mexico (United Mexican States) native
U.S. Dept. Agr., Agr. Res. Serv. (2013)
South America (Pacific rim)
South America (Pacific rim)
Colombia (Republic of) native
U.S. Dept. Agr., Agr. Res. Serv. (2013)


Need more info? Have questions? Comments? Information to contribute? Contact PIER! (pier@hear.org)

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This page was created on 18 JAN 2004 and was last updated on 26 OCT 2006.