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Caulerpa sertularioides
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(Gmel.) Howe 1905 |
Native |
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Division |
Class |
Order |
Family |
Chlorophyta |
Ulvophyceae |
Bryopsidales |
Caulerpaceae |
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Click on pictures for larger images

Caulerpa sertularioides is a small
delicate green alga found only in O‘ahu and Kaua‘i. This species closely
resembles C. taxifolia, the invasive "killer weed" of
the Mediterranean.

Caulerpa
sertularioides attached to hard substrate
on the reef flat.
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Description
Branches, feather-like, flattened, and upright, 3 - 5 cm
high, rising from a creeping stolon (runner), 1 - 2mm in diameter, anchored
by rhizoids to the substrate. Branchlets oppositely attached to midrib,
flattened, slightly curved upwards and tapered at both base and tip. Midrib
is slightly flattened, appearing oval in cross-section. Light green to
yellow green.
This species resembles another native Hawaiian Caulerpa
species, C. taxifolia. C. sertularioides is more delicate and the
branchlets are rounded, compared to the flattened branchlets of C.
taxifolia. The rising branches are also more rounded toward apices,
compared to the more angular, squared-off branches of C. taxifolia.
Structural Features
Thallus non-septate, coenocytic, traversed by trabeculae,
which are extensions of cell wall; reproduction vegetative and sexual,
latter anisogamous. Gametes liberated through papillae that develop on frond
or occasionally on frond.
Habitat
This delicate plant is usually found in warm, quiet waters
in tide pools or on sandy, calm reef flats. It anchors to sandy bottoms or
coral rubble by the creeping rhizoids.
Distribution
Hawai‘i: Northwest Hawaiian
Islands, O‘ahu, Kaua‘i.
Mechanism of Introduction: Indigenous
to Hawai‘i.
Worldwide: Pacific Mexico, Caroline Islands, Micronesia, North Marianas,
Marshall Islands, Gilbert Islands, New Caledonia, Solomon Islands, Japan,
China, Australia, Philippines, Tahiti, Indonesia, Indian Ocean, Caribbean to
Brazil.
Ecology/Impact
Little information has been recorded on Caulerpa
sertularioides. This green alga is a native of Hawai‘i, and is quite
common throughout the world. The Hawaiian version is small and delicate and
grows in small patches in quiet, warm waters on reef flats.
This species is an unassuming, uncommon alga that can easily
be mistaken for C. taxifolia. C. taxifolia is on
invasives
lists elsewhere in the world because of its highly invasive nature. Though
not an invasive in Hawaiian waters, C. taxifolia communities should
be watched for invasive tendencies. For this reason, it is important to
differentiate between the two species.
The extensive rhizoid system of C. sertularioides
aids in nutrient acquisition from sediments. Similar to other Caulerpa
species, recruitment primarily occurs by fragmentation, but C.
sertularioides also reproduces sexually.
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References
Abbott, I.A., 2001, unpublished manuscript.
Eubank, L.L., 1946. Hawaiian Representatives of the Genus
Caulerpa. University of California Publications in Botany, V. 18 :
409-432.
Larned, S.T., 1998. Nitrogen- versus phosphorus-limited
growth and sources of nutrients for coral reef macroalgae. Marine Biology,
132: 409-421.
Littler, D.S. and Mark M., 2000. Caribbean Reef Plants.
OffShore Graphics, Washington, D.C.
Magruder, W.H, and J.W. Hunt, 1979. Seaweeds of Hawai‘i.
Oriental Publishing Company, Honolulu, Hawai‘i.
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Web Pages
Virtual Herbarium.
http://www.botany.hawaii.edu/reefalgae/greenskey.htm
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