Malvaceae
The Malvaceae are trees, shrubs, lianas or herbs comprising about 204 genera and about 2,330 species that are further characterized by the presence of stellate hairs and mucilaginous sap. The leaves are alternate, simple, and often palmately veined and lobed; stipules are present. The flowers are bisexual or functionally unisexual, usually actinomorphic, often associated with conspicuous bracts that form an epicalyx. The perianth consists of usually 5 valvate, distinct or basally connate sepals and usually 5 distinct petals (sometimes lacking) that are often basally adnate to the androecium. The androecium consists of 5-numerous stamens, these distinct, fascicled, or monadelphous with apically divergent filaments; anthers 1- or 2-loculed; staminodes sometimes present. The gynoecium is a single compound pistil of 2-many (sometimes loosely united) carpels with styles and stigmas equaling the carpels in number and distinct, or variously united; the ovary is superior with 2-many locules, each bearing 1-numerous, usually axile ovules. The fruit is a loculicidal capsule, schizocarp, nut, indehiscent pod, aggregate of follicles, drupe, or berry, or samara.
Each "thumbnail" image below is linked to a larger photograph.
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"Tilioid"
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Clappertonia ficifolia
. In this species the perianth is 4-merous and the sepals are petaloid. Numerous stamens are evident.
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Corchorus olitorius,
jute. Note the 5 or 6-merous, differentiated perianth and numerous stamens. Conspicuous stipules are also visible.
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Grewia
occidentalis
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Grewia
sp. Ho'omaluhia Botanic Garden, Kaneohe, HI, fall, 2003.
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Grewia
sp. This photo clearly shows the valvate nature of the calyx that is typical for this family. The petals are somewhat smaller than the sepals. Numerous brownish stamens are nestled around the ovary.
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Tilia
sp., basswood, vic. Corvallis, OR.
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Triumfetta semitriloba,
Sacramento bur. Note the five-merous perianth whorls. In this case the calyx is somewhat petaloid, at least on the front surface.
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"Sterculioid"
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Brachy
chiton acerifolium
, flame tree. Note uniseriate perianth, part of which has been cut away in both flowers illustrated. The middle photo shows a functionally female flower. The right photo depicts a functionally male flower. |
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Brachychiton discolor
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Cola acuminata
, cola nut. 3,4 - male flowers, 5 - male (l) and female (r), 1-5 - Lyon Arboretum, Manoa, HI. |
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Commersonia
sp. |
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Dombeya
sp. Note staminal column with 5 tongue-like staminodes and about 15 stamens. |
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Firmiana
sp. This capsule developed from a single flower. At this point the carpels are essentially distinct and each bears a striking resemblance to a modified leaf with marginal seeds.
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Fremontodendron californica.
In this species the flowers are bisexual and have a well developed corolla. The style of the functional pistil is protruding from the column formed by the monadelphous whorl of 5 functional stamens.
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Guazuma ulmifolia,
West Indian elm. In this species the sepals are somewhat ephemeral. The small yellowish petals are slightly hooded and have a forked brownish appendage. A monadelphous column of greenish stamens surrounds the light green pistil visible in the center of the open flower.
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Heritiera littoralis
, looking-glass tree. The upper flower is functionally female, the lower flower is functionally male. |
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Melochia umbellata
, melochia. |
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Pterygota alata,
Buddhas coconut. These are unisexual flowers with a single perianth whorl consisting of a valvate calyx. One sepal has been removed to reveal the interior of the flowers. On the left is a female flower with vestigial anthers visible at the base of the ovary. The pistil has 5 distinct styles. The male flower on the right has functional stamens united into a monadelphous column.
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Sterc
ulia foetida,
skunk tree. These are functionally unisexual flowers with a single perianth whorl constituting a valvate calyx. On the left is a female flower with the anthers of vestigial stamens visible around the base of the stalked ovary. The flower on the right shows little or no evidence of an ovary. The stamens are functional and united into a monadelphous column.
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Sterculia
sp.
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Theobroma cacao
, cocoa. The seeds in these richly colored fruits are the source of chocolate.
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Waltheria indica,
'uhaloa. This native Hawaiian species is used to brew a tea for treating sore throat. Notice the brown linear stipule at the upper node and the brown stipular scar at the middle and lower nodes.
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"Malvoid"
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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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Abutilon grandiflorum
, hairy Indian mallow. Kealia Trail, Oahu, HI, 2005.
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Alcea rosea
, hollyhock, popular garden ornamental.
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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.
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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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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.
Hawai'i Volcanoes National Park, Hawai'i. |
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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 coulteri
, desert rosemallow, vic. Tucson, AZ, Mar. 2004. |
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Hibiscus denudatus
, rock hibiscus, vic Tucson, AZ, Mar. 2004. |
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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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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 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 waimeae
, koki'o ke'oke'o, koki'o kea, cultivated Foster Botanic Garden, Honolulu, April, 2004, Hawaiian endemic. |
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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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Lagunaria pattersonii
, white wood, handsome tree from E Australia and Lord How and Norfolk Islands. UH Campus, Honolulu, May 2004.
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Malva neglecta
, common mallow, cheeses. Sisters, OR, Sep, 2005. |
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Malva parviflora
, cheeseweed, little mallow. Note the stellate hairs and sch
izocarpic fruit, separating into 1-seeded wedge-shaped sections.
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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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Sida fallax
, ilima.
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Sidalcea
cf.
campestris
, tall wild hollyhock, Finley National Wildlife Refuge, OR, Jul 2004.
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Sidalcea
sp.
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"Bombacoid"
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Adansonia digitata
, baobab, dead rat tree. Tree from tropical Africa with palmately lobed leaves and much enlarged trunk. The Kenyans say the devil planted this tree upside down because of the monstrous appearance with its swollen, bottle-shaped trunk and short dumpy branches sticking up in the air like thick roots. A trunk circumference of 62 feet has been reported in this species. Several trees in Africa are reckoned to be about 5,000 years old. The fragrant white flowers are about 6 inches across and are pollinated by bats. The 6 - 18 inch long fuzzy fruits are on long stalks giving the appearance of a hanging dead rat.
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Bombax ceiba
, red silk cotton tree. Large tree from tropical Asia with prickly trunk and palmate leaves b
earing 3-7 leaflets. The common name refers to hairs (similar to but inferior to kapok) associated with the seeds.
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Bombax glabra
, Guiana chestnut, Malabar chestnut. Tree from tropical S America. The fruit is woody, 4 - 12 inches long, and contains rounded seeds that are edible raw or roasted.
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Ceiba pentandra
, Kapok, 1,2 - Foster Garden, Honolulu, HI, 2004. |
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Ceiba samauma,
lupuna. |
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Chorisia speciosa
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Durio zibethinus
, durian. This is one of the most highly prized of tropical fruits, at least in indonesia where it is used to flavor a variety of foodstuffs, including ice cream. Presumably it is an acquired taste as it has a very heavy odor that is disagreeable to most who encounter it for the first time. |
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Ochroma pyrimidale
, balsa wood.
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Pseudobombax ellipticum
, bombax. Tree from tropical America with showy flowers having conspicuous pink or white stamens, often flowering when the tree is bare.
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Quararibea
sp.
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