Present on Pacific Islands?  yes

Primarily a threat at high elevations?  no

Risk assessment results:  Evaluate, score: 2 (Go to the risk assessment)

Other Latin names:  Pygeum griseum Blume ex Müll. Berol.; Pygeum latifolium Miq.; Pygeum preslii Merr.

Habit:  shrub/tree

Description:  "Tree or shrub.  Twigs pubescent to puberulous, rapidly glabrescent.  Leaves usually elliptic to oblong, sometimes ovate to lanceolate, 2-20 by 1-9 cm, index 1 1/2-3 1/2, base rounded or acute, apex usually acuminate, sometimes (in var. microphylla and in New Guinea specimens of far. grisea) obtuse, sparsely pubescent to glabrous on both sides; nerves (4-) 5-9 (-11) pairs, flat to impressed above, prominent to prominulous beneath, venation inconspicuous to invisible; basal glands 2 (0-4), flat, additional glands usually present; petiole 1/4-1 1/2 (-2) cm, pubescent to puberulous, more or less glabrescent.  Stipules 1 1/2-8 by 1/4-1 3/4 mm, index 2-8 (-12), pubescent to glabrous outside, usually glabrous inside, margin usually glandular (in Philippine specimens of var. grisea sometimes distinctly glandular-serrate).  Racemes solitary, in axils of extant or fallen leaves, 1/2-6 1/2 cm; peduncle 0-1 cm; rachis (sparsely) pubescent.  Bracts up to 2 1/2 mm, usually caducous, the basal ones often with tridentate apex, in Philippine specimens of var. grisea the bracts sometimes large, up to 9 mm long.  Pedicels 0-7 mm, (sparsely) pubescent.  Hypanthium 1 12-4 mm high, pubescent outside, sometimes only sparsely so, entirely glabrous inside or with hairs on bottom.  Perianth segments 6-13, subequal, or more or less distinctly differentiated as sepals and petals, 1/2-2 mm long.  Stamens 15-50; filaments up to 6 mm, glabrous; anthers 1/4-3/4 mm long, in var. microphylla rarely longer.  Ovary usually glabrous, but sometimes with some hairs, rarely (Java specimens of var. grisea especially) distinctly hairy; style up to 7 mm.  Fruits globular to transversely ellipsoid, 6-13 by 7-16 mm, sometimes distinctly or indistinctly pointed (var. tomentosa), glabrous or almost so; endocarp glabrous or sparsely hairy; seedcoat glabrous"  (Kalkman, 1965; pp. 56-57).

Key to the varieties:
1.  Racemes 1/2-1 (-2 1/2) cm, dense.  Pedicels 0-1 (-2) mm.  Leaves usually papyraceous, thin:  var. tomentosa.
1.  Racemes 2-7 cm, loose.  Pedicels 1-7 mm.  Leaves herbaceous or coriaceous:
  2.  Fully developed leaves not more than 7 cm long:  var. microphylla.
  2.  Fully developed leaves at least 8 cm long: var. grisea  (Kalkman, 1965; pp. 58).

Habitat/ecology:  In its native habitat:  Primary and secondary forest, 0-c. 300 m (only in New Guinea often collected above 2000 m, elsewhere rarely from such altitudes (var. grisea); primary and secondary forest, 0-1300 (-1600) m (var. tomentosa); montane and subalpine forest, rarely also in more open vegetation, 1400-3500 m (var. microphylla) (Kalkman, 1965; pp. 58-63).

In Hawai‘i, extensive seedling carpets (more than 100 per square m) with scattered saplings forming thickets in the vicinity of planted trees, Lyon Arboretum, O‘ahu. "Thousands of seedlings and dozens of 1-3 m tall saplings were found, mostly within a 400 sq. m area centered around the original plantings" (Daehler & Baker, 2006; p. 11).

Propagation:  Seeds spread by birds and animals (Staples, Herbst & Imada, 2000; p. 28).

Native range:  Peninsular Burma, Thailand, South Vietnam, throughout Malesia. May be on Taiwan (Kalkman, 1965; p. 57).

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	O‘ahu Island	introduced invasive cultivated	Daehler, Curtis C./Baker, Raymond F. (2006) (p. 11) Vouchers cited: C. Daehler 1097 (BISH), C. Daehler 1098 (HAW), C. Amable 3444 (BISH), D. Orr 84p585 (BISH)
State of Hawaii Hawaiian Islands	O‘ahu Island		Bishop Museum (U.S.A. Hawaii. Honolulu.) (1997) (voucher ID: BISH 655292) Taxon name on voucher: Prunus grisea (C.Müll.) Kalkman
Papua New Guinea Papua New Guinea (eastern New Guinea Island)	Papua New Guinea (eastern New Guinea Island)	native	Kalkman, C. (1965) (p. 57)
Philippines Philippine Islands	Philippine Islands	native	Kalkman, C. (1965) (p. 57)

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	Kalkman, C. (1965) (p. 57)
Malaysia Malaysia	Malaysia (country of)	native	Kalkman, C. (1965) (p. 57)
Singapore Singapore	Singapore (Republic of)	native	Chong, Kwek Yan/Tan, Hugh T. W./Corlett, Richard T. (2009) (p. 72) Critically endangered
Taiwan Taiwan	Taiwan Island	native	Kalkman, C. (1965) (p. 57) Presence as a native species not confirmed.
Thailand Thailand	Thailand (Kingdom of)	native	Kalkman, C. (1965) (p. 57)
Vietnam Vietnam	Vietnam (Socialist Republic of)	native	Kalkman, C. (1965) (p. 57)

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

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

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

References:

Bishop Museum (U.S.A. Hawaii. Honolulu.). 1997. Voucher specimen #BISH655292(Annable, C.R. 3444).

Chong, Kwek Yan/Tan, Hugh T. W./Corlett, Richard T. 2009. A checklist of the total vascular plant flora of Singapore: native, naturalised and cultivated species. Raffles Museum of Biodiversity Research, National University of Singapore. 273 pp.

Daehler, Curtis C./Baker, Raymond F. 2006. New records of naturalized and naturalizing plants around Lyon Arboretum, Mānoa Valley, O‘ahu. In: Evenhuis, Neal L. and Eldredge, Lucias G., eds. Records of the Hawaii Biological Survey for 2004-2005. Part 1: Articles. Bishop Museum Occasional Papers 87:3-18.

Kalkman, C. 1965. The Old World species of Prunus subg. Laurocerasus including those formerly referred to Pygeum. Blumea 13:56-63. .

Staples, George W./Herbst, Derral/Imada, Clyde T. 2000. Survey of invasive or potentially invasive cultivated plants in Hawai‘i. Bishop Museum Occasional Papers No. 65. 35 pp.

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