Hemarthria altissima (Poir.)Stapf & Hubbard, Poaceae

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Present on Pacific Islands?  yes

Primarily a threat at high elevations?  no

Other Latin names:  Manisuris altissima (Poir.) Hitchc.; Rottboellia altissima Poir.

Common name(s): [more details]

English: African jointgrass, Batavian quick grass, halt grass, limpo grass, red quick, red swamp grass, snake grass, swamp couch

Habit:  grass

Description:  "Habit: Perennial. Stolons present. Culms prostrate; 100-250 cm long (long); 2-4 mm diameter; rooting from lower nodes. Lateral branches ample. Ligule a ciliate membrane. Leaf-blades 5-15 cm long; 3-4 mm wide. Inflorescence composed of racemes; exserted. Racemes 1; single; smoothly terete; 4-10 cm long. Rhachis fracturing into irregular segments; flattened; glabrous on margins. Rhachis internodes cuneate. Rhachis internode tip transverse; flat. Spikelets in pairs. Fertile spikelets sessile; 1 in the cluster. Companion sterile spikelets pedicelled; 1 in the cluster. Pedicels fused to internode; united wholly; oblong; flattened; tip rectangular. Sterile spikelets: Companion sterile spikelets well-developed; male; lanceolate; 4-6 mm long; as long as fertile; deciduous with the fertile. Companion sterile spikelet callus truncate. Companion sterile spikelet glumes herbaceous; acute. Companion sterile spikelet lemmas 2; enclosed by glumes. Fertile spikelets: Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets lanceolate; dorsally compressed; 4-6 mm long; falling entire; deciduous with accessory branch structures. Spikelet callus cuneate; glabrous; base truncate; attached obliquely. Glumes dissimilar; exceeding apex of florets; firmer than fertile lemma. Lower glume lanceolate; 1 times length of spikelet; herbaceous; 2-keeled; winged on keel; winged narrowly. Lower glume intercarinal veins distinct. Lower glume surface not waisted, or transversely waisted (near apex). Lower glume apex emarginate, or obtuse. Upper glume oblong; membranous; without keels; 3 -veined. Upper glume apex obtuse to cuspidate. Florets: Basal sterile florets barren; without significant palea. Lemma of lower sterile floret oblong; hyaline; 2 -veined; obtuse. Fertile lemma oblong; hyaline; without keel; 0 -veined. Lemma apex obtuse. Palea hyaline; 0 -veined; without keels. Caryopsis with adherent pericarp; obovoid; dorsally compressed"  (World Grass Species).

"Perennial; culms ascending from a long creeping base, compressed and 2-edged, 40-80 cm long, freely branching toward the ends; blades flat, 3-8 cm, sometimes 10 cm long, compressed; pedicel free or partly adnate to the rachis joint; sessile spikelet 5-7 mm long, the keels of the first glume very narrowly winged toward the apex; pedicellate spikelet 5-6 mm long, acute"  (Hitchcock, 1971).

Habitat/ecology:  In Hawai‘i, "locally common on Maui in pastures and roadsides from Pi‘iholo to Ha‘iku"  (Starr, Starr & Loope, 2004; p. 26).

Propagation:  Seed

Native range:  Africa, temperate and tropical Asia, and Europe (GRIN).

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	Maui Island	introduced invasive	Starr, Forest/Starr, Kim/Loope, Lloyd L. (2004) (p. 26) East Maui. Vouchers cited: Starr & Martz 010629-1 (BISH), Starr & Martz 011030-1 (BISH)

Pacific Rim
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
Indonesia Indonesia	Indonesia (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2011)
Thailand Thailand	Thailand (Kingdom of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2011)
Vietnam Vietnam	Vietnam (Socialist Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2011)

Indian Ocean
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
La Réunion (France) La Réunion Island	La Réunion Island	native	U.S. Dept. Agr., Agr. Res. Serv. (2011)
Mauritius Mautitius Islands (Mauritius and Rodrigues)	Mauritius Island	native	U.S. Dept. Agr., Agr. Res. Serv. (2011)

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

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

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

References:

Clayton, W.D./Harman, K.T./Williamson, H. 2011. World Grass Species: Descriptions, Identification, and Information Retrieval [GrassBase - The Online World Grass Flora]. The Board of Trustees, Royal Botanic Gardens, Kew.

Starr, Forest/Starr, Kim/Loope, Lloyd L. 2004. New plant records from the Hawaiian Archipelago. In: Evenhuis, Neal L. and Eldredge, Lucius G., eds. Records of the Hawaii Biological Survey for 2003. Part 2: Notes. Bishop Museum Occasional Papers. 79:20-30.

U. S. Government. 2011. Integrated Taxonomic Information System (ITIS) (on-line resource).

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