At
the right you see me standing in a big field in southern Mississippi, surrounded by millions
of Canada Goldenrods, Solidago canadensis. In the fall, few wildflowers and weeds
put on such a brilliant show as goldenrods.Goldenrods are
members of the Composite Family, so by no means
do their blossoms have the same structure as our Standard
Blossom. If you run across a goldenrod, try to find the following parts of the actual
goldenrod flower.
In
the above photo you can see that the flowering yellow top -- the inflorescence --
of each goldenrod plant consists of numerous arching, fingerlike structures. On our Blossom Arrangement Page we see that this kind of
inflorescence is known as a panicle. The fingerlike structures are
branches of the goldenrod's panicle. At the left you see one of those branches magnified
several times. Each of those cylindrical things with a fuzzy top is a head
consisting of several flowers.
At the right you see a much-magnified head. If you don't know
about ray and disk flowers, check out our Composite
Family page. The outwardly flaring items that in other blossoms we might call petals
are actually ray flowers. Inside the head are visible several disk
flowers. A couple of the disk flowers have anthers rising above them. This whole
collection of ray and disk flowers is held together in a slender, greenish-yellow, cuplike
structure known as the involucre. If you were holding the head in your
hand, you could separate the longish, flattish, tongue-like involucral bracts
from one another.
At the left you see a much-much magnified disk flower, with a
less-magnified ray flower shown in the yellow-framed inset at the lower right in the
picture. Now things are beginning to look a little more like our Standard Blossom, for the
corolla tube has five petal-like lobes. The entire disk flower measures only about 3/16ths
of an inch long (4 mm).
The pappus consists of stiff bristles atop the inferior
ovary (as explained on our Standard
Blossom page). Later both of these items will enlarge, while other flower parts will
wither and fall off. The inferior ovary will become a special kind of hard, dry fruit
called an achene, and the pappus will develop into a kind of
"parachute" that will help the achene travel to a new location on the wind. |