Hibiscus & Malvaceae: Hibiscus brackenridgei ssp. brackenridgeiHibiscus malvaceae

• Hibiscus and other Malvaceae •

CULTIVATION • CONSERVATION • EDUCATION

Hibiscus and other Malvaceae: The genus Hibiscus is part of the Malvaceae, a taxonomic family that comprises thousands of species. Some members of this family possess considerable economic value, such as some Gossypium species (Cotton), while others are used as food sources, such as Abelmoschus esculentus (Okra), and Hibiscus sabdariffa (Roselle), used in jams and teas. Some species are used as fiber sources for jute and rope making, like Hibiscus cannabinus (Kenaf), and various Corchorus species (Jute). From times past (but perhaps to a lesser degree now), others supplied durable timber for woodworking, like some Talipariti and Thespesia species, and Hibiscus campylosiphon, an impressive tree from the Philippines.

Despite the undeniable value of the above-mentioned species, the worldwide fascination with the Malvaceae is credited to the unparalleled popularity of one of this family's most ornamental members, Hibiscus rosa-sinensis. Hibiscus rosa-sinensis cultivars are the result of crosses (both ancient and modern) between a limited number of species (from Lilibiscus ―a section of the genus Hibiscus containing about 10 species), the majority coming from the Mascarene Islands in the Indian Ocean and the Hawaiian Islands in the Pacific. This complex hybrid group was derived from a number of species that included most if not all of the following: Hibiscus arnottianus, Hibiscus boryanus, Hibiscus denisonii, Hibiscus fragilis, Hibiscus genevii, Hibiscus kokio, Hibiscus liliiflorus, Hibiscus schizopetalus, and Hibiscus storckii. Sadly, nearly all of these (as well as numerous other Malvaceae species) are now considered extinct or facing extinction in their natural habitats. For additional information on Hibiscus rosa-sinensis cultivars, go to the Hibiscus rosa-sinensis page.

The biological diversity (biodiversity) of our planet is rapidly decreasing in great part due to the direct and indirect consequences of human activity. Ironically, it is also through human activity and intervention that threatened and endangered species are offered their best chances for survival. Thankfully, in recent years, there has been increasing awareness regarding the profound importance of earth's biodiversity linked with the critically urgent necessity for human action to safeguard it. In the Biblical book of Genesis, we read "and the Lord God took the man and put him in the Garden of Eden to tend and guard and keep it", (Gen 2:15), conferring on humankind a role as Earth's primary caretaker. This 'tending, guarding and keeping' is best defined as having responsibility for the care and protection of the earth (stewardship), and affirms our commission for the wellbeing of this planet's vast community of life. Ultimately, stewardship of the earth, and conservation of its ecosystems is the responsibility of all people, not merely that of national governments.

The main strategies for conserving species are commonly referred to as ex situ conservation (out of the natural habitat) and in situ conservation (within the natural habitat). Ex situ conservation is accomplished through the efforts of botanical gardens, educational institutions, private gardens, and even seed banks. Although ex situ conservation is regarded as complementary to in situ conservation, in some situations it is the only option, ―the last resort when in situ conservation is no longer possible due to habitat loss and destruction. Some of the plants presented on these pages have suffered that fate and are currently classified as extinct, threatened or endangered in their natural habitats. In order to ensure their continued survival, an applied approach of 'cultivation, conservation and education' must be promoted. It is for this purpose that the entries found on this site are offered. Your feedback is greatly appreciated, especially in regard to errors.

Concerning the Historical References listed throughout these pages, please keep in mind that portions of the infomation presented may be outdated or incorrect. In addition, any dietary or medical information should be regarded as anecdotal. These references are included simply because they offer a glimpse of the horticultural history that is attached to many of these extraordinary plants. ―GB

Tuesday, December 29, 2009

Hibiscus brackenridgei ssp. brackenridgei

Hibiscus brackenridgei | Ma'o hau hele, Native Yellow Hibiscus, Brackenridge's Rosemallow

Hibiscus brackenridgei is Hawai'i's State flower, and is listed as an endangered species. It was named after William Brackenridge (1810-1893), an American horticulturist and superintendent of the National Botanic Garden in Washington D.C. Hibiscus brackenridgei is native to dry forests and shrub lands at elevations from 120 to 800m (400 to 2,600 ft). It is a shrub that grows up to 3m in height, with maplelike leaves and bright yellow flowers. It is found on all the main Hawaiian islands except Ni'ihau and Kaho'olawe, but it is not common in any location. Hibiscus Brackenridgei is closely related to the Australian Hibiscus divaricatus and some believe that it may not be specifically distinct from it (Wagner, Manual of the flowering plants of Hawaii, 1990).

Hibiscus brackenridgei varies in appearance among islands but generally falls into three subspecies:
      ssp. brackenridgei of Maui, Molokai, Lanai and the Big Island,
      ssp. mokuleianus, The Mokulei Rosemallow of Oahu and Kauai.
      ssp. molokaianus is an extremely rare 3rd subspecies.

The most visible difference between these subspecies is in the leaves and stems. The leaves of ssp. mokuleianus have more serrated margins and pink veins with tiny spines on the branches. Ssp. brackenridgei, on the other hand, has leaves with more rounded margins and yellow veins, and it lacks the tiny spines on its branches.

Historical Reference: Mr. Rock sent in from the island of Oahu (Territory of Hawaii) a showy tree hibiscus (Hibiscus brackenridgei), bearing yellow flowers 6 inches across. From Honolulu, Hawaii. Seed presented by J. F. Rock. Received June 30, 1920. "A striking and well-marked rather rare species with a shrubby erect stem, 4 to 5 feet high, stiff spreading branches, and rather stout, very leafy flowering stalks. It is worthy of cultivation on account of its showy yellow flowers. The smooth, bright-green leaves on long petioles are rounded in outline, 3 to 4 inches in diameter and 5 to 7-lobed, somewhat resembling those of the common grapevine. The spreading yellow corolla is about 6 Inches across. Found In the scrub vegetation of the leeslde of Oahu, East and West Maul, and Lanai."

This extremely rare species of Hibiscus, which Mr. Rock found growing among the stones at the base of a cliff on the windward side of the island of Oahu, is a thing of rare beauty when covered with its large yellow flowers. Since it grows under arid and rather severe conditions it may be found useful as an ornamental plant in some parts of tropical America which, because of unfavorable climate and soil, are not well suited to the cultivation of many of the common tropical ornamentals. The deep canary-yellow flowers of this exceedingly rare Hibiscus are 6 inches across. Only a few wild plants are in existence, and the species seems not to have found its way into American horticulture, although Hillebrand called attention to the possibilities of its culture more than 30 years ago.

   Plant inventory, Issues 61-70
   Agricultural Research Center-West (U.S.). Northeastern Region
   The Dept., 1922

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• Hibiscus and other Malvaceae •

Tuesday, December 29, 2009

Hibiscus brackenridgei ssp. brackenridgei

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