Digitaria henryi Rendle, Poaceae

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Present on Pacific Islands?  yes

Primarily a threat at high elevations?  no

Common name(s): [more details]

Chinese: heng li ma tang

Habit:  grass

Description:  "Prostrate, mat-forming grass.  Culms 5-15 cm or more in length, the lower nodes glabrous.  Leaf sheath glabrous, striate, keeled; ligule membranous, truncate, 1-2 mm long.  Leaf blade narrowly lanceolate, 1-3 cm long, 2-4 mm wide, surfaces with scattered, tubercle-based hairs, margins finely scabrous.  Inflorescence of 1-3 more or less horizontal racemes 1-4 cm long, not spreading at maturity, rachis 3-angled with scabrous margins.  Spikelets lanceolate, 2-3 mm long, in unequally stalked pairs.  Lower glume reduced to a scale, upper glume 3/4 as long as the spikelet, acute, 3-nerved, margins hairy.  Sterile lemma as long as the spikelet, 7-nerved, with hairy lateral veins crowded near the margins.  Distinguishable by its prostrate grass habit, small leaves, glabrous leaf sheath, leaf surfaces with long hairs, 1- or 3-branched racemes that do not spread at maturity, unequally aired spikelets, and lower glume reduced to a scale."  (Whistler & Steele, 1999; pp. 82-83).

Description from GrassBase.

Habitat/ecology:  "Common in the Old World tropics as a weed of sunny disturbed places" (Whistler & Steele, 1999).  On Kwajalein, Marshall Islands, "uncommon as a weed of lawns" (Whistler & Steele, 1999; pp. 82-83).

Propagation:  Seed

Native range:  Taiwan (Whistler & Steele, 1999; pp. 82-83).

Presence:

Pacific
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
American Samoa Manu‘a Islands	Ofu Island		Yuncker, T. G. (1945) (p. 23) Voucher cited: Yuncker 9550 (BISH)
American Samoa Manu‘a Islands	Ta‘u Island		Yuncker, T. G. (1945) (p. 23) Voucher cited: W. Harris 71 (BISH)
Kiribati Phoenix Islands	Kanton Island	introduced	Fosberg, F. R./Stoddart, D. R. (1994) (p. 37) Not seen in 1973 or 1975. Voucher cited: Degener & Degener 24647 (US)
Marshall Islands Ralik Chain	Kwajalein (Kuwajleen) Atoll	introduced	Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1987) (p. 37)
Marshall Islands Ralik Chain	Kwajalein (Kuwajleen) Atoll	introduced invasive	Whistler, W. A./Steele, O. (1999) (pp. 82-83) Vouchers cited: Herbst 8957, Herbst 8998, Whistler 11192, Whistler 11199, Whistler 11239, Whistler 11240 Uncommon.

Pacific Rim
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
China China	China (People's Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2011)
China China	Hong Kong	native	Wu, Te-lin (2001) (p. 332) On grassy hillslopes.
Japan Ryukyu Islands	Ryukyu Islands	native	U.S. Dept. Agr., Agr. Res. Serv. (2011)
Taiwan Taiwan	Taiwan Island	native	U.S. Dept. Agr., Agr. Res. Serv. (2011)

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

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

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

References:

Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce. 1987. A geographical checklist of the Micronesian monocotyledonae. Micronesica 20:1-126.

Fosberg, F. R./Stoddart, D. R. 1994. Flora of the Phoenix Islands, central Pacific. Smithsonian Institution, Washington. Atoll Research Bulletin 393. 60 pp.

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

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.

Wu, Te-lin. 2001. Check List of Hong Kong Plants. Hong Kong Herbarium and the South China Institute of Botany. Agriculture, Fisheries and Conservation Department Bulletin 1 (revised). 384 pp.

Yuncker, T. G. 1945. Plants of the Manua Islands. Bishop Mus. Bull. 184. Bishop Museum Press, Honolulu. 73 pp.

Zhengyi, Wu/Raven, Peter H./Deyuan, Hong. 2011. Flora of China (online resource).