Report to the Republic of Palau: 2008 update on Invasive Plant ...

Scattered individuals <strong>of</strong> Xenostegia [=Merremia] tridentata (African morningvine) [voucher
9906], probably introduced and previously recorded (Fosberg et al. (1979); Fosberg, O<strong>to</strong>bed et
al. (1980)) were found growing along with Anisea martinicensis in a hydroseeded area along <strong>the</strong>
Compact Road.
Zornia gibbosa is present along <strong>the</strong> Compact Road in Airai State [voucher 9817] and in
cultivation in Aimeliik State.
Koror State
Koror
Cala<strong>the</strong>a majestica [=C. princeps], probably an escape from cultivation, spreads by rhizomes.
While a Hawai‘i/Pacific risk assessment performed for this species indicates that it is <strong>of</strong> low risk
based on <strong>the</strong> information available, it should be moni<strong>to</strong>red for spread.
Several examples <strong>of</strong> Calliandra surinamensis (pink powder puff) were seen in cultivation. It is
reported <strong>to</strong> be an invader in Fiji.
Livis<strong>to</strong>na chinensis (Chinese fan palm, fountain palm) was seen in cultivation. It is known <strong>to</strong> be
invasive in Florida and Hawai‘i. The Hawai‘i/Pacific Islands weed risk assessment for this
species gives a score <strong>of</strong> 5, “evaluate fur<strong>the</strong>r”.
A newly naturalized Convolvulaceae species for <strong>Palau</strong>, Merremia hederacea (ivy woodrose)
[voucher 9708] was found down <strong>the</strong> road from <strong>the</strong> Yuhi Hotel, climbing over trees and o<strong>the</strong>r
vegetation. This was <strong>the</strong> only infestation <strong>of</strong> this species observed. From <strong>the</strong> size <strong>of</strong> <strong>the</strong>
infestation it was probably present but missed in <strong>the</strong> previous survey. It was previously recorded
from Guam and Yap in Micronesia (Fosberg et al., 1979). It is native <strong>to</strong> <strong>the</strong> Philippines and may
have been introduced from <strong>the</strong>re.
Pilea nummulariifolia (creeping Charlie) is probably an escape from cultivation on Koror. It
spreads vegetatively. While it has a risk assessment score <strong>of</strong> 0 (“low risk”) it should be
moni<strong>to</strong>red for spread.
Ngerkebesang
An example <strong>of</strong> Costus woodsonii (Indian-head ginger, red cane) in cultivation was seen and
collected [voucher 9721]. The plant spreads vegetatively by forming new plantlets and may also
spread by rhizomes. It has spread quite widely in <strong>the</strong> Lyon Arboretum in Hawai‘i, suggesting
that it may also spread by seed (Daehler & Baker, 2006). It has a risk assessment score <strong>of</strong> 11,
“high risk”.
Episcia reptans has been planted at <strong>the</strong> <strong>Palau</strong> Pacific Resort [voucher 9720]. Small examples
were also seen in cultivation and as a garden escape in Koror and in Airai State, Babeldaob. This
species, with variegated leaves and a pretty red flower, is an attractive bedding plant and is thus
likely <strong>to</strong> become widespread through cultivation. It is shade-<strong>to</strong>lerant and spreads aggressively by
s<strong>to</strong>lons. It can probably be easily transplanted and forms a dense ground cover. It is highly
likely <strong>to</strong> spread outside <strong>of</strong> cultivation, crowding out native plants and inhibiting regeneration.
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