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Back in my school days I had a problem remembering the flowery details.
Pistils, stamens, sepals, petals—well, the petals and sepals were easy, but the rest, not. For some reason the curriculum did not include what the parts were used for. Oh, there was never a question that there were boy parts and girl parts, or that bees had a role in bringing the parts together (pollination), or that until they did, offspring could not happen. But the wonder, the differences of these parts, took awhile to sink in. The change in perception came with a growing experience of the “why” of these parts. A spring like this one in 2005 is a great opportunity to explore the “why.”
Here are some of the whys of this season’s personal favorite, the brown-eyed primrose, or just browneyes, Camissonia claviformes. Browneyes is a member of the evening primrose family and there are
a few things we can expect:
4 sepals that protect the flower in bud, reflexed back after opening; and 4 petals, the colorful parts that attract from afar. The petals are attached to the tube at the
top of the stalk-shaped ovary. The inside of the tube is a glistening mass of brownish maroon cells—the browneyes which act as a signal to the pollinator, and produce nectar.
8 stamens (the boy
or “men’s” part), each with an anther sack containing the pollen, and connected by a filament to the tube.
1 pistil (the girl part). The pistil has three parts: the stigma, which reaches up and out to
receive pollen, connected by the style (down which a pollen grain must travel) to the ovary containing the ovules, which, after pollination, develop into seeds (in humans the ovules develop into
babies.) All the different Camissonia have pistils shaped like clubs. Stigmas for other groups of the family may be divided into four thread-like parts (see the dune evening-primrose).
The common name for this genus is Suncups, because many of its members are yellow and open in the early morning.
But many of them, like browneyes, are white, and they open in the evening. White petals are good at reflecting light, and are common to night blooming flowers.
The flowers all grow on the same side of the stem. The flowers bloom in a sequence moving from the bottom of the stem towards the top.
The top of the stem bends, clustering the flowers at the top, making them obvious to a cruising pollinator. The cluster maintains its attractive position because the distracting buds are tucked underneath and the pollinated flowers loose their petals (see top illustration).
I have never seen the pollinator, but I suspect it is a small moth. Why? The anther is long and narrow and delicately but firmly poised at mid-section atop the filament.
Take your finger and touch one—it will rock back and forth. The anthers produce masses of sticky cobweb-like threads full of pollen.
The pistil, with its clubbed head, is physically and chemically more complicated than the stamen because it is the route by which pollen grains reach the ovule for fertilization. Mistakes can
be costly. Therefore, the pistil has tricks of timing and placement. To discover some of these tricks look at all the flowers on a showy head early in the evening, as the action is starting.
With the youngest flower(s) the thread-like pollen is visible, the stigma is not, and browneyes are not yet colored.
The flower is getting ready to be visited. Then you will notice flowers with a glistening naked stigma hanging in front of the anthers, with browneyes visible. Next look for flowers where there are pollen grains on the stigma and the anthers look shriveled.
As this sequence develops, a hairy moth visits the flower(s) guided into the center by the brown eyes. The moth first touches the stigma, delivering pollen it picked up from previous visits to
other flowers as it then brushes against the anthers, which rock back and forth (but don’t break) against the hairy body depositing strands of pollen.
The moth is searching for a drinkable reward, oblivious to all this pollinating business.
After pollination the petals turn pink and fall off, leaving the developing ovary, which resembles a baseball bat.
See for yourself. Gently dissect a flower, isolating each part, but also watch all the parts working in concert. In the evening visit the dune evening primroses out near Ironage Road in
Twentynine Palms to see how they are similar but also different.
Writer and naturalist Pat Flanagan leads tours of the Oasis of Mara at 29 Palms Inn at 8:30 a.m. every Sat./Sun.
(weather permitting). She is also Marketing Coordinator for Twentynine Palms Chamber of Commerce.
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