Carr, Gerald D.

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My research interests focus on biosystematics, speciation, and adaptive radiation in plants. Most of my work has involved chromosome evolution in a group of closely related Pacific Coast and Hawaiian genera that include the well-known Haleakala silversword. However, I am also collaborating with a number of other researchers on such aspects as molecular evolution, physiological diversification, and phytochemistry of these taxa. Our goal has been to provide a comprehensive, multidisciplinary perspective on the spectacular adaptive radiation that characterizes the Hawaiian element of this group.


Dr. Gerry Carr, Emeritus Professor
Department of Botany
1975 PhD. Botany
Oregon State University


Recent Submissions

Now showing 1 - 5 of 8
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    The Later Publications of Harold St. John
    (University of Hawaii Press, 1994-04) Carr, Gerald D.
    This paper lists the bibliography after 1980 of Dr. Harold St. John professor emeritus of the University of Hawaii Botany Department, who died 12 December 1991.
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    A Reassessment of Dubautia (Asteraceae: Heliantheae - Madiinae) on Kaua'i
    (University of Hawai'i Press, 1999-04) Carr, Gerald D.
    Aggressive botanical exploration of Kaua'i has yielded nearly 200 collections and two new species of Dubautia since the last monograph of the genus was published about a dozen years ago. This paper presents an updated key to the 13 species of Dubautia found on Kaua'i, summarizes and discusses the importance and systematic impact of recent collection data, and provides new maps to reflect the current knowledge of species distributions.
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    A Remnant Greensword Population from Pu'u 'Alaea, Maui, with Characteristics of Argyroxiphium virescens (Asteraceae)
    (University of Hawaii Press, 1998-01) Carr, Gerald D. ; Medeiros, Arthur C.
    Two unusual greenswords occurring on Pu'u 'Alaea in 1989 reportedly possessed vegetative features characteristic of the presumed extirpated species Argyroxiphium virescens Hillebr. One of these Pu'u 'Alaea plants flowered in August 1989, allowing detailed comparisons with preserved specimens of A. virescens as well as other species and hybrids of Argyroxiphium native to East Maui. These comparisons suggest that the unusual Pu'u 'Alaea greenswords represent remnants of hybridization between the now presumably extinct A. virescens and the more common Haleaka silversword, A. sandwicense subsp. macrocephalum (A. Gray) Meyrat, that still occurs at and adjacent to this site. The estimated pollen fertility of 62% in the Pu'u 'Alaea plant is consistent with this interpretation. Recovery of a few embryos from fruits of the plant that flowered in 1989 and the possibility of tissue culture of the remaining living plant at Pu'u 'Alaea apparently represent the last opportunities to conserve any vestige of A. virescens.
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    Two New Species in the Hawaiian Endemic Genus Dubautia (Compositae)
    (University of Hawaii Press, 1979-07) Carr, Gerald D.
    Two species of the Hawaiian genus Dubautia (subgenus Railliardiaster) are described as new. Dubautia herbstobatae (n = 13) is from Ohikilolo Ridge in the Waianae Mountains of Oahu; D. waianapanapaensis (n = 13) is from the upper Hana rain forest on Haleakala, Maui.
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    Reproductive Biology and Uniform Culture of Portulaca in Hawaii
    (University of Hawaii Press, 1990-04) Kim, Insun ; Carr, Gerald D.
    Ten taxa of Portulaca that occur in Hawaii (P. lutea, P. molokiniensis, P. oleracea, P. pi/osa, P. sclerocarpa, P. villosa, two imperfectly known species, and two cultivars) were included in a study of reproductive biology and uniform cultivation. The response of plants under uniform conditions upholds the merger of the reputed Hawaiian endemic P. cyanosperma with P. pilosa. All Portulaca taxa in Hawaii are autogamous, and in most instances large numbers of seeds are set even when the flowers are totally undisturbed. Some taxa are facultatively cleistogamous, but even in chasmogamous forms the flowers are open for only about 3-9 hr. The cultivars were the only taxa observed to attract pollinators, but P. molokiniensis, which was not studied in nature, appears to have adaptations for biotic pollination. Most of the portulac as studied have capsular fruit that require about 13-17 days to mature, but in P. sclerocarpa the fruits are thick-walled and indehiscent and require about 28 days for maturation. The life cycle ranges from about 8 weeks in most cases to several months in P. molokiniensis. However, individuals of most taxa typically flower and fruit man y times during one growing season. Seeds were generally nondormant, but partial seed dormancy was encountered in P. molokiniensis.