Dilleniidae: Malvales. The Malvaceae are herbs, shrubs, or trees comprising about 75 genera and perhaps as many as 1,500 species that are further characterized by the presence of stellate hairs and mucilaginous sap. The leaves are alternate, simple, and usually palmately veined; stipules are present. The flowers are almost always bisexual and actinomorphic. The perianth consists of 5 valvate, distinct or basally connate sepals and 5 distinct petals that are usually basally adnate to the androecium. The androecium consists of very numerous monadelphous stamens with apically divergent filaments bearing 1-celled anthers. The gynoecium is a single compound pistil of 2-many carpels, an equal number of styles or style branches, and a superior ovary with 2-many locules, each bearing 1-numerous ovules. The fruit is a loculicidal capsule, schizocarp, berry, or samara.
Each "thumbnail" image below is linked to a larger photograph.
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Hibiscus tiliaceus, hau. Reddish style branches can be seen extending beyond the end of the monadelphous staminal column that bears many anthers. The staminal column and the petals are adnate at the base of the flower. | ||
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Hibiscus arnottianus, koki'o ke'oke'o. This close view shows part of the staminal column and the emergent style branches of this endemic Hawaiian hibiscus. Each of the individual stamens diverging from the column are terminated by a 1-celled or "half" anther. | ||
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Hibiscus schizopetalus, coral hibiscus. Shrub from E Africa with slender arching branches and pendant, red flowers with feathery reflexed petals. The pollen of this hibiscus is often used in Hawaii for producing new varieties. | ||
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Hibiscus esculentus, okra. This edible species releases large quantities of muscilaginous sap that gives gumbo its slimy consistency. | ||
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Hibiscadelphus giffardianus, hau kuahiwi. Although nearly all Malvaceae have actinomorphic flowers, a few species endemic to Hawaii are exceptions. Hibiscadelphus flowers secrete large quantities of nectar and have a curved shape and configuration that closely matches the bills of native honeycreepers that are thought to have been important pollinators of these plants. This photo also shows narrow bracts at the base of the tubular calyx. These bracts, sometimes called an epicalyx, are a common occurrence in the family. | ||
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Montezuma speciosissima, maga. Tree from Puerto Rico, grown in Hawaii as an ornamental but valued elsewhere for its durable timber for fence posts and furniture. Note "half" anthers on the staminal column in the right photo. | ||
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Kokia cookei, koki'o. This endemic Hawaiian genus also has zygomorphic flowers but not as strongly so as Hibiscadelphus. | ||
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Abutilon spp. Left, A. sandwicense; Center, A. menziesii, ko'oloa 'ula; Right, A. erimitopetalum. These are all three of the endemic Hawaiian species in this genus. Note typical floral morphology and palmately veined leaves. | ||
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Gossypium tomentosum, ma'o. The short brownish fibers on the seeds of the Hawaiian cotton are not commercially useful but the Hawaiian plants have been used in cotton breeding programs in attempts to improve disease resistance in commercial cotton. | ||
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Gossypium barbadense, cotton. This is one of the species used commercially. Note the long, white seed hairs that are used to spin cotton thread. |
