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Digitaria stenotaphrodes

Thickhead Grass

Multimedia & Additional Resources

Type	Description	Download
Image:	Plant and detail of spike	51KB
Image:	Compare: Digitaria pacifica (Line Islands)	59KB

General Information

COMMON NAMES: Thickhead Grass

TRADITIONAL NAMES: Vayavaya (PK)

GLOBAL DISTRIBUTION: NATIVE Carolines - Tuvalu - Pukapuka/Suwarrow - Tuamotu (atolls only)

COOK ISLANDS STATUS: Native; N.Group only - very rare (PK and SW only); Land

SIGNIFICANCE LIST: ; Nationally endangered - seriously

KEY FEATURES: An ascending, tufted grass, to 70cm high, with a cylindrical flowering head; spikes 4-6, erect, parallel, ~joined at base, 6-15cm; spike-midrib distinctly winged; SPIKELET lanceolate (c.4:1) with second glume about 25% of spikelet length. LEAVES to 25x1cm.

SIMILAR SPECIES: Line Islands Thickhead-Grass (Digitaria pacifica - not yet known in the Cook Islands) has spikes to 10 (vs to 6); spikelet ovate - c.2:1 L:B (vs lanceolate - c.4:1 L:B); second glume round and 10% length of spikelet (vs arrowlike and 25% of spikelet).

Enlarged Image of 'Digitaria stenotaphrodes'

Cook Islands Distribution

View Distribution Map

Southern Group: - Makatea: -
RR	MG	AT	MK	MT	AK	PL	TK	MN
-	-	-	-	-	-	-	-	-

Northern Group: Present
TN	MH	RK	PK	NS	SW
-	-	-	+	-	+

Key to Symbols

blank	no data
-	absent	L	localised
X	extinct 'naturally'	W	widespread
XQi	quarantine intercepted	R	recent
XQe	eradicated	?	query preceding category
P	present	T?	taxonomic query
S	seasonal	nn	present, said to have no name
O	occasional	?1	present, name not investigated
++++	very common	?2	presence not verified, no name recorded
+++	common	N/A	absent, name not expected
++	uncommon
+	rare
Cook Islands islands: RR =Rarotonga, MG = Mangaia, AT =‘Ātiu, MK=Ma‘uke, MT=Miti‘āro, AK=Aitutaki, PL=Palmerston, PN=Penrhyn, MN=Manuae, TK=Takūtea, TN=Tongareva (TS=Tongaleva Spoken, TW=Tongareva Written, they say "el" but write "r"), MH=Manihiki, RK=Rakahanga, PK=Pukapuka, NS=Nassau, SW=Suwarrow. After a Polynesian name: ^=orthography query. Countries and other: FIJ=Fiji, WT=Wallis & Futuna, SAM=Samoa, TON=Tonga, NIU=Niue, CK=Cook Islands, CKM=Cook Islands Māori, FP=French Polynesia, AUS=Australs, SOC=Societies, TAH=Tahiti, TUA=Tuamotus, MQS=Marquesas, MNG=Mangareva, PIT=Pitcain group, EAS=Easter Island, HAW=Hawai‘i, NZ=New Zealand, NZM=New Zealand Māori

Scientific Taxonomy

Digitaria stenotaphrodes (Nees)
SYNONYMS: Syntherisma pelagica

TAXONOMY: PLANTAE; ANTHOPHYTA (=Angiospermae); LILIOPSIDA (=Monocotyledones); COMMELINIDAE; Cyperales; POACEAE

More Information

SIGNIFICANCE NOTES -
BIODIVERSITY: Nationally endangered - seriously. Comment: Known from one plant on Pukapuka and one plant on Suwarrow.

Vouchers & References

Vouchers:
Pukapuka: specimen+photo, Motu Kō on track entering eastern forest from runway, 2/2004, G.McCormack with ID as Digitaria stenotaphrodes - second glume 25% of lanceolate spikelet. Suwarrow: specimen, One Tree Motu, 8/1993, B.Sykes.

References:
None recorded.

Data Update History (information):
zTX, zB02, zM05a, zD02, zupD04a

Web Resources

Citation Information

McCormack, Gerald (2007) Cook Islands Biodiversity Database, Version 2007.2. Cook Islands Natural Heritage Trust, Rarotonga. Online at http://cookislands.bishopmuseum.org.
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