Rhynchospora caduca Elliott, Cyperaceae

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Present on Pacific Islands?  yes

Primarily a threat at high elevations?  no

Common name(s): [more details]

English: anglestem beaksedge

Habit:  herb

Description:  "Perennials with short-creeping rhizomes; culms loosely to moderately densely tufted, 60-120 cm tall, 1.8-3 mm in diameter near base, 3-4-nodose below the inflorescence, trigonous, smooth.  Leaves basal, a few cauline and well-spaced, herbaceous, linear, shorter than the culm, 3-6 mm wide; sheaths 2-5 cm long, the cauline ones green, the basal ones reddish brown or yellowish brown.  Inflorescences of 4-5 well-spaced, anthelate partial panicles, these decompound, 2-7 cm long, 1.5-3 cm wide, moderately dense, the peduncles exserted, branches numerous, 1-3 cm long, once or twice further branched, each bearing 3-5 spikelets, the lowest 2 leaf-like bracts longer than the subtending partial panicle, the upper bracts as long as or shorter than the subtending partial panicle; spikelets brown, solitary or in clusters of 2-3, subsessile, ovate, 3.5-4.5 mm long, ca. 2 mm wide, subterete; glumes 6-8, the middle 3-6 flower-bearing, 2-4 of them perfect, brown to rusty brown, ovate to broadly so, acute, membranous, margins hyaline, the slender and conspicuous midnerve prolonged into a straight mucro or short awn, the flower-bearing glumes 2.8-3.7 mm long, 2-3 mm wide; perianth bristles 6, longer than the achene (incl. the style base); style base deltoid, 0.6-0.8 mm high and wide, ciliate.  Achenes broadly obovate, lenticular, 1-1.6 mm long, 1-1.4 mm wide, transversely undulate-rugose and cancellate with longitudinally oblong cells"  (Wagner et al., 1999; p. 1428).

Habitat/ecology:  In Hawai‘i, "sparingly naturalized in wet, disturbed areas, 320-1,400 m" (Wagner et al., 1999; p. 1428).

Propagation:  Seed, rhizomes.

Native range:  Southern US

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	Hawai‘i (Big) Island	introduced invasive	Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (p. 1428) Voucher cited: Shinbara H110 (BISH)
State of Hawaii Hawaiian Islands	Kaua‘i Island	introduced invasive	Wagner, Warren L./Herbst, Derral R. (1995) (pp. 18-19) Voucher cited: Hume & Levine 332 (BISH, PTBG)
State of Hawaii Hawaiian Islands	Maui Island	introduced invasive	Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (p. 1428)
State of Hawaii Hawaiian Islands	Moloka‘i Island	introduced invasive	Wysong, Michael/Hughes, Guy/Wood, K. R. (2007) (p. 4) Voucher cited: K.R. Wood & Hughes 10563 (PTBG)
State of Hawaii Hawaiian Islands	O‘ahu Island	introduced invasive	Wagner, Warren L./Shannon, Robynn K./Herbst, Derral R. (1997) (p. 56) Voucher cited: Takeuchi 8516 (BISH)

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. (2013)

Control:  If you know of control methods for Rhynchospora caduca, please let us know.