Ischaemum polystachyum J.S.Presl, Poaceae

Click on an image for links to BIGGER PICTURES

Present on Pacific Islands?  yes

Threat only at high elevations?  no

Risk assessment results:  Reject, score: 20 (Go to the risk assessment)

Other Latin names:  Ischaemum digitatum var. polystachyum ((presl) Hackel

Common name(s): [more details]

Chuukese: fatil

English: paddle grass

Kosraean: mah

Pohnpeian: reh padil

Habit:  grass

Description:  "Sprawling grass, with long decumbent culms finally ascending to 4 ft.; pubescence of nodes, sheaths and blades variable; racemes 4-7, 3 in. long, spreading; rachis joints and pedicels trigonous, the angle scabrous or short-ciliate, about 4 mm long, bowed equally away from each other; fertile lemma of sessile spikelet bearing a twisted geniculate awn" (Henty, 1969; p. 117).

"Habit: Perennial. Rhizomes elongated. Culms decumbent, or prostrate; 30-150 cm long; without nodal roots, or rooting from lower nodes. Culm-nodes pubescent. Ligule an eciliate membrane; 2.5 mm long. Leaf-blades 5-25 cm long; 3-20 mm wide. Leaf-blade surface glabrous, or pubescent. Inflorescence: Inflorescence composed of racemes. Racemes 2-5(-8); paired, or digitate; unilateral; 3-15 cm long. Rhachis fragile at the nodes; angular; ciliate on margins. Rhachis internodes cuneate; flat and forming a U or V shape with the pedicel in rear view, or flat and forming a U or V shape with the pedicel in rear view and with a basal circular pore between internode and pedicel. Rhachis internode tip transverse; cupuliform. Spikelets in pairs. Fertile spikelets sessile; 1 in the cluster. Companion sterile spikelets pedicelled; 1 in the cluster. Pedicels cuneate; 1 times length of internode; ciliate. STERILE Spikelets: Companion sterile spikelets well-developed; containing empty lemmas, or male; elliptic; laterally compressed; 4-7 mm long; as long as fertile; separately deciduous. Companion sterile spikelet glumes chartaceous; keeled; 7-9 -veined; muticous. Companion sterile spikelet lemmas 2; enclosed by glumes; 1-awned. Fertile spikelets: Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets lanceolate, or oblong; dorsally compressed; 4-7 mm long; falling entire; deciduous with accessory branch structures. Spikelet callus oblong; 1-1.5 mm long; bearded; base obtuse; inserted. Glumes: Glumes dissimilar; reaching apex of florets; firmer than fertile lemma. Lower glume oblong; 1 times length of spikelet; chartaceous; much thinner above; 2-keeled; keeled above; keeled laterally; wingless, or winged on keel; winged above; 5-9 -veined. Lower glume surface convex; glabrous, or pilose, or villous. Lower glume apex entire, or dentate; 2 -fid. Upper glume lanceolate; 1 times length of spikelet; chartaceous; 1-keeled; keeled above; 3-5 -veined. Upper glume apex acuminate. Florets: Basal sterile florets male; with palea. Lemma of lower sterile floret lanceolate; 1 times length of spikelet; membranous; 3-5 -veined; acute. Fertile lemma oblong; 4-6 mm long; membranous; without keel; 3 -veined. Lemma margins ciliate. Lemma apex lobed; 2 -fid; incised 0.5 of lemma length; awned; 1 -awned. Principal lemma awn from a sinus; geniculate; 5-20 mm long overall; with twisted column. Column of lemma awn glabrous. Palea 1 times length of lemma" (World Grass Species).

Habitat/ecology:  In New Guinea in roadsides, garden clearings and grasslands from sea level to 6,000 feet (Henty, 1969; p. 117).

Propagation:  Seed

Native range:  Philippines to New Guinea, Polynesia.

Presence:

Pacific
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
Commonwealth of the Northern Mariana Islands (US) Northern Mariana Islands	Rota Island	native	Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1987) (pp. 46-47)
Commonwealth of the Northern Mariana Islands (US) Northern Mariana Islands	Rota Island	native	Fosberg, F. R./Sachet, M.-H. (1982) (pp. 65-67) Voucher cited: Hosaka 3036 (US, BISH, POM, NY, L)
Commonwealth of the Northern Mariana Islands (US) Northern Mariana Islands	Saipan Island	native	Raulerson, L. (2006) (p. 9)
Federated States of Micronesia Chuuk Islands	Puluwat (Pwonowót) Atoll	native	Manner, H. I./Mallon, E. (1989) (p. 35) var. intermidium (Brogn.) Fosb. & Sachet. Voucher cited: Manner & Mallon 140 (GUAM), Manner & Mallon 298 (GUAM)
Federated States of Micronesia Kosrae Island	Kosrae Island	native	Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1987) (pp. 46-47)
Federated States of Micronesia Kosrae Island	Kosrae Island	native	Space, James C./Waterhouse, Barbara/Denslow, Julie S./Nelson, Duane/Waguk, Erick E. (2000) (p. Voucher specimen) Specimen collected: BMW 5761 (BISH, BRI, GUAM)
Federated States of Micronesia Kosrae Island	Kosrae Island		Lorence, David H./Flynn, Tim (2005) (p. 9) Voucher cited: Lorence 7875 (PTBG)
Federated States of Micronesia Kosrae Island	Kosrae Island	native	Fosberg, F. R./Sachet, M.-H. (1982) (pp. 65-68) Var. intermedium (Brongn.) Fosberg & Sachet; voucher cited: d'Urville (P, 2 sheets, syntypes; US, fragment)
Federated States of Micronesia Pohnpei Islands	Pohnpei Island	native	Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1987) (pp. 46-47)
Federated States of Micronesia Pohnpei Islands	Pohnpei Island	native	Space, James C./Falanruw, Marjorie (1999) (p. 5)
Federated States of Micronesia Pohnpei Islands	Pohnpei Island	native	Waterhouse, Barbara (year unknown) (p. Voucher specimen) Specimen collected: BMW 5785 (BISH, BRI)
Federated States of Micronesia Pohnpei Islands	Pohnpei Island	native	Lorence, David H./Flynn, Tim (1998) (p. 12) var. intermedium (Brogn.) Fosb. & Sachet, voucher cited: Lorence 7905 (PTBG)
Federated States of Micronesia Pohnpei Islands	Pohnpei Island	native	Fosberg, F. R./Sachet, M.-H. (1982) (pp. 65-68) Var. chordatum (Trin.) Fosberg & Sachet; vouchers cited: Ledermann 13915 (B); var. intermedium (Brongn.) Fosberg & Sachet; vouchers cited: Fosberg 26249 (US, BISH, POM, NY), Fosberg 26304a (US)
Federated States of Micronesia Yap Islands	Ifalik (Ifaluk) Atoll	native	Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1987) (pp. 46-47)
Federated States of Micronesia Yap Islands	Ifalik (Ifaluk) Atoll	native	Fosberg, F. R./Sachet, M.-H. (1982) (pp. 65-68) Var. intermedium (Brongn.) Fosberg & Sachet; voucher cited: Fosberg 47253 (US, BISH, POM, NY)
Federated States of Micronesia Yap Islands	Yap (Waqab) Island	native	Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1987) (pp. 46-47)
Federated States of Micronesia Yap Islands	Yap (Waqab) Island	native	Fosberg, F. R./Sachet, M.-H. (1982) (pp. 65-68) Var. chordatum (Trin.) Fosberg & Sachet; vouchers cited: Fosberg 46594 (US), Fosberg 46521 (US, BISH), Fosberg 25534 (US, BISH), Cushing 380a (US), Hosaka 3283 (US, BISH); var. intermedium (Brongn.) Fosberg & Sachet; voucher cited: Cushing 448 (US)
Federated States of Micronesia Yap Islands	Yap (Waqab) Island		Bishop Museum (Honolulu) (1946) (voucher ID: BISH 1001457) Taxon name on voucher: Ischaemum polystachyum J.S.Presl
Guam Guam Island	Guam Island	native	Stone, Benjamin C. (1970) (pp. 234, 236)
Guam Guam Island	Guam Island	native	Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1987) (pp. 46-47)
Palau Palau (main island group)	Babeldaob Island	native	Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1987) (pp. 46-47)
Palau Palau (main island group)	Babeldaob Island	native	Fosberg, F. R./Sachet, M.-H. (1982) (pp. 65-68) Var. chordatum (Trin.) Fosberg & Sachet; vouchers cited: Canfield 608 (US), Hosokawa 9643 (US), Hosokawa 6779 (US, fragment), Timberlake & Johannes 3027 (US); var. intermedium (Brongn.) Fosberg & Sachet; voucher cited: Fosberg 25726 (US, BISH, POM, NY)
Palau Palau (main island group)	Babeldaob Island		Bishop Museum (Honolulu) (1991) (voucher ID: BISH 609877) Taxon name on voucher: Ischaemum polystachyum J.S.Presl
Palau Palau (main island group)	Babeldaob Island		Bishop Museum (Honolulu) (1996) (voucher ID: BISH 661048) Taxon name on voucher: Ischaemum polystachyum var. chordatum (Trin.) Fosberg & Sachet
Palau Palau (main island group)	Babeldaob Island		Bishop Museum (Honolulu) (1996) (voucher ID: BISH 661162) Taxon name on voucher: Ischaemum polystachyum var. chordatum (Trin.) Fosberg & Sachet
Palau Palau (main island group)	Babeldaob Island		Bishop Museum (Honolulu) (1996) (voucher ID: BISH 661194) Taxon name on voucher: Ischaemum polystachyum var. chordatum (Trin.) Fosberg & Sachet
Palau Palau (main island group)	Koror Island	native	Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1987) (pp. 46-47)
Palau Palau (main island group)	Koror Island	native	Fosberg, F. R./Sachet, M.-H. (1982) (pp. 65-68) Var. chordatum (Trin.) Fosberg & Sachet; vouchers cited: Hosaka 3343 (US, BISH), Fosberg 47502 (US, BISH); var. hillii Fosberg & Sachet; voucher cited: Hill 6 (US, holotype; GUAM, isotype); var. intermedium (Brongn.) Fosberg & Sachet; voucher cited: Otobed PW-10091
Palau Palau (main island group)	Malakal Island	native	Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1987) (pp. 46-47)
Palau Palau (main island group)	Malakal Island	native	Fosberg, F. R./Sachet, M.-H. (1982) (pp. 65-67) Var. chordatum (Trin.) Fosberg & Sachet; vouchers cited: Evans 561 (US, BISH, POM, NY)
Palau Palau (main island group)	Ngerkebesang Island	native	Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1987) (pp. 46-47)
Palau Palau (main island group)	Ngerkebesang Island	native	Fosberg, F. R./Sachet, M.-H. (1982) (pp. 65-67) Var. chordatum (Trin.) Fosberg & Sachet; vouchers cited: Fosberg 25656 (US, BISH)
Palau Rock Islands	Aulupse‘el Island	native	Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1987) (pp. 46-47)
Palau Rock Islands	Aulupse‘el Island	native	Fosberg, F. R./Sachet, M.-H. (1982) (pp. 65-67) Var. chordatum (Trin.) Fosberg & Sachet; vouchers cited: Fosberg 32366 (US, BISH)
Papua New Guinea Papua New Guinea (eastern New Guinea Island)	Papua New Guinea (eastern New Guinea Island)	native	U.S. Dept. Agr., Agr. Res. Serv. (2007)
Philippines Philippine Islands	Philippine Islands	native	U.S. Dept. Agr., Agr. Res. Serv. (2007)
Solomon Islands Solomon Islands	Solomon Islands	native	Hancock, I. R./Henderson, C. P. (1988) (p. 84)

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. (2007)
Malaysia Malaysia	Malaysia (country of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2007)

Comments:  Although this is a native grass, it is very abundant along roadsides and in disturbed areas. It is particularly aggressive on Pohnpei.

Fosberg et al. (1987; pp. 46-47) list varieties polystachyum, present on Rota and Guam; chordatum (Trin.) Fosb. & Sachet, present on Palau (Babeldaob, Koror, Ngarakabesang, Malakal, and Aulupse'el), Yap, and possibly Pohnpei; hillii Fosb. & Sachet, present on Palau (Koror); and intermedium Brongn., present on Palua (Babeldaob, Koror), Yap, Ifaluk, Pohnpei, and Kosrae.

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

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

References:

Bishop Museum (Honolulu). 1946. Voucher specimen #BISH 1001457 (Fosberg, F.R. 25534).

Bishop Museum (Honolulu). 1991. Voucher specimen #BISH 609877 (Herbst, D.R. 9384).

Bishop Museum (Honolulu). 1996. Voucher specimen #BISH 661048 (J.V.Ward 279).

Bishop Museum (Honolulu). 1996. Voucher specimen #BISH 661162 (J.V.Ward 249).

Bishop Museum (Honolulu). 1996. Voucher specimen #BISH 661194 (J.V.Ward 260).

Clayton, W. D./Harman, K. T./Williamson, H. 2002. World Grass Species: Descriptions, Identification, and Information Retrieval (online resource).

Fosberg, F. R./Sachet, M.-H. 1982. Micronesian Poaceae: Critical and distributional notes. Micronesica 18(2):45-102.

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

Hancock, I. R./Henderson, C. P. 1988. Flora of the Solomon Islands. Research Bulletin No. 7. Ministry of Agriculture and Lands, Honiara. 203 pp.

Henty, E. E. 1969. A manual of the grasses of New Guinea. Department of Forests, Division of Botany, Botany Bull. No. 1. Lae, New Guinea. 215 pp.

Lorence, David H./Flynn, Tim. 1998. Checklist of the plants of Pohnpei. Unpublished checklist. National Tropical Botanical Garden, Lawai, Hawai‘i. 21 pp.

Lorence, David H./Flynn, Tim. 2005. Checklist of the plants of Kosrae. Unpublished checklist. National Tropical Botanical Garden, Lawai, Hawai‘i. 23 pp.

Manner, H. I./Mallon, E. 1989. An Annotated list of the vascular plants of Pulawat Atoll. Micronesica 22:23-63.

Raulerson, L. 2006. Checklist of Plants of the Mariana Islands. University of Guam Herbarium Contribution 40:1-69. .

Space, James C./Falanruw, Marjorie. 1999. Observations on invasive plant species in Micronesia. USDA Forest Service, Honolulu. Report to the Pacific Islands Committee, Council of Western State Foresters. USDA Forest Service, Honolulu. 32 pp.

Space, James C./Waterhouse, Barbara/Denslow, Julie S./Nelson, Duane/Waguk, Erick E. 2000. Invasive plant species on Kosrae, Federated States of Micronesia.  USDA Forest Service, Honolulu. 43 pp.

Stone, Benjamin C. 1970. The flora of Guam. Micronesica 6:1-659.

U.S. Dept. Agr., Agr. Res. Serv. 2007. National Genetic Resources Program. Germplasm Resources Information Network (GRIN). Online searchable database.

Waterhouse, Barbara. 0. Barbara Waterhouse, pers. com.