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Asclepiadaceae
Milkweed Family
By: George
Rogers
Note: The
Asclepiadaceae are merged into the Apocynaceae in some modern classifications (SMI).
Informal
characterization (with data from BA2): When separated from Apocynaceae, a
worldwide family of about 130 genera and 2000 species, mostly milky-juiced
shrubs, vines, and herbs of warm climates. The leaves are typically opposite or
whorled, and the flowers are in umbels or cymes. The floral structure is the
most salient aspect of the Asclepiadaceae, with 5 sepals, 5 petals, and 5
stamens, these highly modified to have appendages (the corona, such as the horns
on milkweed flowers) and fused to each other, to the corolla, and to the pistil
in such a way that the pistil/stamen combination forms a hump in the center of
the flower with 5 slits along the sides. Flanking the inside edges of the slits
are pollen masses called pollinia. These are connected in pairs across the top
of the slit by a thread that catches on the legs of pollinating insects, pulling
the pollinia up through the slit.
Asclepiadaceae cultivated in Florida include:
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Carrion-Flowers |
Stapelia (and Huernia) species |
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Giant
Milkweed |
Calotropis gigantea |
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Milkweeds |
Asclepias curassavica and additional species of Asclepias, some
native
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Stephanotis |
Stephanotis floribunda |
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Wax Vine |
Hoya
carnosa (and additional species) |
Key to
Asclepiadaceae Cultivated in Florida
1. Plants
vines…5
1. Plants
not vines…2
2. Plants
cactuslike succulents…Stapelia or Huernia
2. Plants
not succulents…3
3. Plants
over 8’ tall, with violet flowers…Calotropis
3. Plants <
6’ tall, with red, yellow, or orange flowers (or rarely purplish)…4
4. Flowers
purplish...Swamp Milkweed (Asclepias incarnata)
4. Flowers
red or red and yellow…Scarlet Milkweed (Asclepias curassavica)
5. Leaves
semisucculent, waxy; flowers waxy and tubeless…Hoya
5. Leaves tough
but not thick and waxy; flowers with elongate tubes…Stephanotis
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