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Taxonomy: |
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Gossypium tomentosum (Malvaceae)
Synonyms:
Gossypium hirsutum f. tomentosum
Gossypium sanvicense
Gossypium tomentosum var. parviflorum
Common Names:
Hawaiian Names:
Ma'o
Huluhulu
English Name:
Hawaiian Cotton
Classification:
Kingdom: Plantae-Plants
Subkingdom: Tracheobionta-Vascular plants
Superdivision: Spermatophyta-Seed plants
Division: Magnoliophyta-Flowering plants
Class: Magnoliopsida-Dicotyledons
Subclass: Dilleniidae
Order: Malvales
Family: Malvaceae - Mallow family
Genus: Gossypium L. - Cotton
Species: Gossypium tomentosum Nutt. ex Seem. - Ma`o
(Wagner, W. L., Herbst, D. R., and S. H. Sohmer. 1999. Manual of the Flowering Plants of Hawai`i. Revised Edition. Volume 1. Bishop Museum Special Publication 97. University of Hawai`i Press, Bishop Museum Press, Honolulu, Hawai`i.)
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Description: |
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Gossypium tomentosum is a shrub that grows from 0.5 to 1.5 m tall and can spread extensively forming clumps from 1.5 to 3 m in diameter.
The leaves are wider (3-10 cm) than they are long with 3 or 5 lobes that are rounded to pointed at the apex. The venation of the leaves is palmate meaning the primary veins diverge from a single point at the base of the leaf. The leaves have branched hairs on both the top and lower surface which gives them a silvery, gray-green appearance. The flowers are bright yellow (about 6 cm in diameter) and are typically borne either singly or in clusters of 1-3 flowers in the leaf axils. Each flower is subtended by an involucre made up of three bracts (15-25 mm long) with margins that are irregularly and sharply toothed. These bracts can also be seen during the formation of the fruit which is a woody capsule that is 1.2-1.8 cm long. This capsule dries and breaks open when it is mature to release 6-12 seeds each of which is 5 mm long and is covered by reddish brown fibers.
(Wagner, W. L., Herbst, D. R., and S. H. Sohmer. 1999. Manual of the Flowering Plants of Hawai`i. Revised Edition. Volume 1. Bishop Museum Special Publication 97. University of Hawai`i Press, Bishop Museum Press, Honolulu, Hawai`i.)
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Geographic Distribution: |
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Gossypium tomentosum is an endemic species meaning that is only found in Hawai`i. It is found in dry coastal shrublands from sea level to 120 m on on the leeward side of all the main islands except Hawai`i and Kaua`i.
Ma`o flourishes on sand or weathered clay and rocky substrates in this harsh environment which receives less than 500 mm of rainfall annually and is subject to large temperature fluctuations.
(Wagner, W. L., Herbst, D. R., and S. H. Sohmer. 1999. Manual of the Flowering Plants of Hawai`i. Revised Edition. Volume 1. Bishop Museum Special Publication 97. University of Hawai`i Press, Bishop Museum Press, Honolulu, Hawai`i.)
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Food Uses: |
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The oil extracted from the New World species Gossypium barbadense and Gossypium hirsutum is purified for the production of cottonseed oil.
The semi-toxic oil gossypol is produced in glands in the seed and must be processed in order to render this oil edible.
(Simpson, B. B. and M. C. Ogorzaly. 2001. Economic Botany: Plants in our World. 3rd edition. McGraw-Hill, New York.
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Status: |
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Gossypium tomentosum is an endemic shrub that was previously considered vulnerable by the International Union for the Conservation of Nature and Natural Resources but is not currently listed on the IUCN Red List.
IUCN. 2004 IUCN Red List of Threatened Species. . 15 Apr. 2006.
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Species Interconnections and Interdependencies: |
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Gossypium tomentosum is thought to be pollinated by moths (Order: Lepidoptera) while other Gossypium species are pollinated by bees (Order: Hymenoptera).
The flowers are also different to those of the other Gossypium species as they stay open at night whereas most Gossypium flowers open in the morning and wither by the end of the same day.
(Animal and Plant Health inspection Service, USDA. 15 Apr. 2006.
http://www.aphis.usda.gov/brs/cotton.html.)
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Preservation and Conservation Strategies: |
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Gossypium tomentosum is currently found in remnant fragments of dry coastal shrublands on the leeward side of O`ahu, Maui, Kaho`alawe, Lana`i and Ni`ihau.
It is no longer found on Kaua`i although it was historically found there. Currently research is being conducted on the potential for introgression of genetic material from the cotton species that have become naturalized in Hawaii, Gossypium hirsutum and G. barbadense.
(Animal and Plant Health inspection Service, USDA. 15 Apr. 2006.
http://www.aphis.usda.gov/brs/cotton.html.)
(DeJoode, D. R. and J. F. Wendel. 1992. Genetic diversity and origin of the Hawaiian Islands cotton, Gossypium tomentosum. American Journal of Botany. 79(11): 1311-1319.)
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Scientific Research: |
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The short, brown seed fibers of the Hawaiian cotton species, Gossypium tomentosum, are not utilized for the production of fiber.
This species has however been utilized in cotton breeding programs for the production of flowers lacking nectaries in an effort to reduce insect damage within cotton crops. Current research also involves crosses of G. tomentosum with other cotton species for investigation of the potential beneficial effects on fiber yield and quality, plant stature, pest resistance, and heat and drought stress tolerance.
(DeJoode, D. R. and J. F. Wendel. 1992. Genetic diversity and origin of the Hawaiian Islands cotton, Gossypium tomentosum. American Journal of Botany. 79(11): 1311-1319.)
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Native Legends and Names: |
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The Hawaiian name ma`o refers to the coloration of the flowers and can be translated as "yellow green".
The alternative name huli huli translates as "hairy" in reference to the hairs present on the surface of the leaves. The genus name Gossypium comes from the Greek word for cotton - "gossypion". The specific epithet tomentose means woolly in reference to the long fibers present on the seeds.
(DeJoode, D. R. and J. F. Wendel. 1992. Genetic diversity and origin of the Hawaiian Islands cotton, Gossypium tomentosum. American Journal of Botany. 79(11): 1311-1319.)
(Plowden, C. C., 1970. A Manual of Plant Names, Philosophical Library, New York.)
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Indigenous Practices: |
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The flowers of ma`o produced a yellow dye that was traditionally used in kapa production. Both the flowers and the seeds are used for making beautiful leis.
(Abbott, I A. 1992. Lā`au Hawii`i: Traditional Hawaiian Uses of Plants. Bishop Museum Press, Honolulu, Hawai`i.)
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NTBG Herbarium Data: |
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