General Information

COMMON NAMES: Umbrella Plant, Umbrella Palm, Umbrella Sedge GLOBAL DISTRIBUTION: NATIVE e.Africa - Arabia COOK ISLANDS STATUS: Introduced - Recent (c.1920), Naturalised; Land, lowlands - inland valleys; along streams SIGNIFICANCE LIST: Ornamental leaves, erosion control; Weed - moderate (localised, Rarotonga) KEY FEATURES: Perennial, tall-stemmed sedge, to 150cm. RHIZOMES horizontal, stout, woody. STEM top slightly 3-angled. LEAVES BASAL reduced to bladeless sheaths, to 20cm. LEAVES INVOLUCRAL umbrella-like whorl, slender, most of similar length, to 30x2cm. FLOWERS clustered on axillary stalks (=rays) to 8cm; then spikes to 2cm; then spikelets to 1cm with 10-30 pale green flowers, to 2mmL. NUT 3-angled, to 1mmL.

Cook Islands Distribution

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

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

Cyperus involucratus Rottbøll 1772
SYNONYMS: Cyperus alternifolius auct. non Linnaeus; Cyperus alternifolius Linnaeus subsp. flabelliformis (Rottbøll) Kükenthal; Cyperus flabelliformis Rottbøll 1773, nom. illegit.

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

SIGNIFICANCE NOTES -
POSITIVE SIGNIFICANCE: Ornamental leaves, erosion control
NEGATIVE SIGNIFICANCE: Weed - moderate (localised, Rarotonga). Comments: Forming dense thickets mainly along streams. Difficult to control, but also beneficial in stablising the banks.

Vouchers:
None Recorded.

References:
p.84 Neal - In Gardens of Hawaii
p.356 Hortus 3rd
p.338 Royal Hort. Soc. Index of Garden Plants
p.1/251 A.C.Smith - Flora Vitiensis Nova
p.22 R Wilder - Flora of Rarotonga

Data Update History (information):
zTX, zB02, zM04a, zD04a, zupD05b

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