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Flowers& Fruits-4-Rosaceae-1

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We will use the Rose Family RosaOrnFlr.jpg (26775 bytes)to explore some important variations in flower structure and relate these to fruit types. This family is one of the most importat fruit-producing taxa, and most of the commercial fruits are well known. The most common examples of this taxon do not grow in the tropics. However, some ornamental roses can be grown in Hawaii.

The Genus Rubus includes blackberries and rasberries. There is a native Rubus species that is being displaced by an alien race and this is an area of concern for Conservation Biologists.

RubusFlr-1Lab.jpg (45607 bytes)
A] This Rubus flower has Five Petal, Many Stamens & Many Simple Carpels in its Apocarpous Gynoecium

B]

RubudAndroGynoLab.jpg (67145 bytes)

RubusGynoMacroLab.jpg (48893 bytes)
C] Another species with relatively large Carpels. The Stigma is readily visible for each Carpel. Note the Green Sepals.RubusBudMicroLSLab.jpg (73868 bytes)
D] Microscopic Image of a Rubus Flower Bud. Relate this to all of the macrophoto to the Right!WB01570_.gif (184 bytes)

rubus_sp_fr_greenLab.jpg (71037 bytes)
E] Rubus flower post pollination. The Ovary of each Carpel is swollen due to successful fertilization. Note the withered Stigmas & Styles.

FragariaFlrLongSecMacroLabHue.jpg (58187 bytes)
F] Long Section through a Fragaria (Strawberry) flower: Compare with the Image to the Left
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RubusFruitsWholeMacro.jpg (43645 bytes)
G] The Finished Product
RubusFruLab.jpg (49068 bytes)
H] A closer inspection reveals the fact that the fruit is composed of many fruitlets that developed from each simple carpel. This is an Aggregate Fruit.
RubusMatreFruitJPEG.jpg (54677 bytes)

Strawberry is in the genus Frageria. I cheated and used the long section of a Fragaria flower above. The flower structure is nearly identical to Rubus at the outset. However, it is the Receptacle of Frageria which becomes fleshy and is regarded as the "fruit". The carpels become tiny dry indihescent fruits called Achenes.

FragariaOverall.jpg (43980 bytes)
Strawberry Plants

FragariaFlrLSMacro.jpg (72216 bytes)
Strawberry Flower Longitudunal Section

StrawberryBudLSMicro.jpg (46342 bytes)
Long section through a flower bud

StrawberryBudLSMicroClose.jpg (30686 bytes)
High magnification showing part of the Gynoecium

StrawberryFruTwo.jpg (40340 bytes)
Strawberry Fruits: The bulk of this Accessory Fruit is derived from the swollen Receptacle. The true fruits are the tiny, seed-like achenes on the surface.

StrawberryFruAchLab.jpg (49486 bytes)
Close-up of a Strawberry Fruit

This is a type of "Accesory Fruit" because other floral parts besides the Ovary wall are part of the fruit.

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