Pollination and Plant Families

2-D says, “Mmm, yummy pollen! The kinds of flowers I like to visit usually have more than enough to go around, so while I’m drinking flower nectar, I’ll suck up some pollen along with it. Hey, I need the protein. Sometimes those flowers get pollen all over me, and then, when I visit another flower cluster, a bunch of that pollen rubs off and pollinates those flowers. It’s a win-win situation. My favorite plants get pollinated so they can, eventually, make seeds to grow more plants, and I get a meal out of the deal. The plants reward me with their nectar and a bit of their pollen to eat, and I reward the plants by helping to transfer their pollen.”

Means of Transferring Pollen:

Male Pine Cones
Wind-Transferred Pollen
Insect-Transferred Pollen
Some plants, such as pine, grass, and ragweed are wind-pollinated, so their reproductive strategy is to produce large amounts of pollen in hopes that some makes it to the female. Many other plants depend on animals to spread their pollen. In that case, the animal involved is called a pollinator. Not all animals can pollinate all plants, but certain types of animals such as birds, butterflies, moths, bees, beetles, wasps, bats, and flies, typically pollinate certain types of plants. This is a mutualistic relationship where both the plant and the pollinator(s) benefit each other. Some plants are very specific with respect to what animal is able to serve as a pollinator, and have special modifications (special shape, etc.) to attract that pollinator or exclude other would-be pollinators. Others plants are more general and are more attractive to a wider variety of pollinators, but the risk here is that the pollen may not get to the “right” species if the pollinator visits a different type of flower next.

Yucca Flowers
There are special cases where a plant species and a species of pollinator are totally dependent on each other. These cases are examples of coevolution, the joint evolution of a plant and its animal pollinator. In coevolution, each of the species involved serves as a source of natural selective pressure on the other. A more formal definition for coevolution is “the mutual evolutionary influence between two species.” One example of this type of coevolution would be the yucca plant and the yucca moth. The female moth lays her eggs in the flowers, simultaneously pollinating the plant, and the caterpillars develop within the seeds in the ovary of the plant. For the plant, the loss of a few seeds to caterpillars is a price worth paying to insure pollination. The yucca moth is the only animal that is the right size and shape to pollinate yucca flowers.

Beetle on Thistle
Beetle and Thistle
In order to make use of animal pollinators, plants must:

The “reward” is not always food (nectar). There is a tropical orchid with a flower that looks and smells like the female of a certain species of wasp. Males of this species emerge one week before the females, but these orchids are already blooming. The male wasps smell the orchids, “think” they’ve found a female, and try to copulate. The texture of the flowers is such that they “feel” like a female wasp, but the poor males just can’t get it to work, leave to find a more cooperative mate, and end up transferring pollen instead.

Adaptations of Flowers for Given Pollinators:

The adaptations exhibited by any given flower depend on the type of pollinator the flower is designed to attract. Various pollinators have differing adaptations and means of gathering pollen and/or whatever nectar, etc. a flower has to offer.

UV Landing Patterns
Weigh the Bee
 Bees  don’t see red, but do see blue, yellow, and ultraviolet. Thus, bee-pollinated flowers are mostly yellow (some blue) with ultraviolet nectar guides or “landing patterns.” The flowers typically have a delicate, sweet scent, which the bees can smell. Usually the nectar is at the end of some type of small, narrow floral tube which is the right length to fit the tongue of the particular species bee that pollinates that plant. Bee-pollinated flowers typically have a sturdy, irregular shape with some type of specifically-designed landing platform. An example of this is snapdragons, where only a bee of just the right size and weight is able to trigger the flower to open, while all others (which are too small or too heavy) are excluded. Typically, pollen sticks to the “fur” of a bee or else the bees collect the pollen in specially-modified areas on their legs.

Butterfly on Milkweed
Orange-Red Color
+ Landing Platform
 Butterflies  are diurnal and have good vision but a weak sense of smell. They can see red. Butterfly-pollinated flowers are brightly-colored (even red) but odorless. These flowers are often in clusters and/or are designed to provide a landing platform. Butterflies typically walk around on a flower cluster, probing the blossoms with their tongues. Examples of butterfly-pollinated flowers would be many members of the plant family Compositae, where many small flowers are arranged into a flat-topped head, and other plants, such as the milkweeds, where the flowers occur in large clusters. The individual flowers are typically tubular with a tube of suitable length for butterflies.

Most  moths  are nocturnal and have a good sense of smell. Moth-pollinated flowers typically are white or pale colors so they will be at least somewhat visible on a moonlit night. Often, moth-pollinated flowers may only be open at night. They typically use a strong, sweet perfume to advertise their presence in the darkness, and typically this odor is only exuded at night (evolutionarily, it doesn’t make sense to waste energy producing attractant in the daytime when it is useless). Moths are hover-feeders, so these flowers have deep tubes to precisely match the length of a specific moth’s tongue. One famous story relates that Charles Darwin found an extrordinarily long, tubular flower in South America and predicted that some day, someone would find a moth with a tongue of matching length. After much searching, around a hundred years later, indeed, this moth was found. More recently, a flower with an even-longer tube was found on Madagascar, and Dr. Gene Kritsky out at Mt. St. Joe has been interested in trying to find the “missing” moth that goes with it. In moth-pollinated flowers, the petals are flat or bent back so the moth can get in, and hover close to the flower. Moonflower is moth-pollinated.

Bright Red, Please! (©DBF)
 Birds , especially hummingbirds, have good eyes and seem to be especially attracted to red. However, birds have a poor sense of smell (yes, it is OK to carefully put fallen babies back into the nest — the parents cannot smell your scent). Bird-pollinated flowers are brightly-colored, especially red but lack odor. Their petals are recurved to be out of the way. Hummingbirds are hover-feeders, so the flowers are designed to dust the bird’s head/back with pollen as the bird probes the flower for nectar. Flowers such as Columbine, red Salvia, Trumpet Vine, and Fuchsia are favorite nectar sources for hummingbirds.

 Bats  are nocturnal with a good sense of smell. While many bats depend on echolocation rather than sight to navigate, those species which serve as pollinators do have good vision. Also, bats which pollinate flowers have long, bristly tongues to lap up nectar and pollen. Since these flowers are open at night, they are white or light-colored so they’ll be visible in moonlight. Bat-pollinated flowers have a musty smell like the smell of bats. These flowers are large and sturdy to withstand insertion of the bat’s head as it licks nectar and pollen.

Wild Ginger
Meat-Red + on Ground
 Flies  are attracted to rotting meat. Thus, fly-pollinated flowers may be nondescript or brownish red in color, and typically have a strong, “bad,” rotten sort of smell.

 Ants and/or Beetles  might find flowers on the ground to be easier to locate and visit. Those flowers might be even more attractive if they sort-of look and smell like (rotting) flesh.

Pollination Game

This kaleidoscope design is derived from a photograph of a California Poppy. Hidden beneath these twelve squares are six flowers and six pollinators. Click on pairs of squares to expose their pictures, and try to match the flowers with the most-likely pollinators. OK... Javascript weirdness... it wouldn’t show the second picture clicked before “turning them back over.” So, I got that fixed – sort-of. It will now display the first two pictures clicked, then when you click on a third one, it will go back and check the first two. I know, that makes it easy to lose track of whether you’re on a “first” or “second” click, but eventually you should be able to get to the end of it. When you click anywhere on the squares after you match the last pair, the pictures will reload in a different order so you can try again.

#00 #01 #02 #03
#04 #05 #06 #07
#08 #09 #10 #11

Plant Families

Botanists group species of plants based on a number of characteristics. As previously discussed, botanists pay particular attention to how the flowers are put together. Other important flower characteristics include the number of flower parts present (3 petals?, 4?, 5?), whether the flower parts are fused or modified in any way (for example, trumpetvine and petunia flower petals are fused to form a tube), and whether the petals (for example) are all shaped the same (rose, lily) or are very different in shape (pansy, snapdragon). Botanists also consider the shape and arrangement of the leaves. Yet another characteristic is the type of fruit the plant has (How is/are the seed(s) packaged?).

Tree or
Type of
Type of
Other Photograph
and Link
Genus Pinus
tree needles* none pine cone* gymnosperm Family Pinaceae
Genus Trillium
lilies, tulips,
herb blades w/
parts in 3s,
often sepals
and petals
look alike
  monocot Family Liliaceae
herb blades w/
usually small,
seeds like
wheat or
monocot Family Gramineae
buttercups, columbine, larkspur
herb   5 petals*
ovary above
  dicot Family Ranunculaceae
mustard, radish,
herb   4 petals*
6 stamens
  olive fam.
has 4 pet. &
2 stamens
Family Cruciferae
Genus Acer
tree most simple
  seed with
a wing
  Family Aceraceae
rose, cherry,
bramble, apple
both alternate
simple or
5 petals*
ovary under
rose hips
  Family Rosaceae
pea, bean,
locust tree,
both compound
petals joined
so pea flower
  Family Leguminosae
Genus Quercus
oaks, beech
tree simple

acorn*   Family Fagaceae
carrot, dill,
Queen Anne’s
herb   many flowers
arranged in an
seeds like
dill or
  Family Umbelliferae
mints, basil,
thyme, sage
herb simple
some petals
joined so
  stems are
Family Labiatae
daisy, dandelion,
herb   many flowers
arranged in
one head*
    Family Compositae

Note that some of these families have two family names. Some of the names like “Cruciferae” and “Compositae” are older, more traditional family names, but more recently, botanists decided that, for the sake of conformity, all plant family names should end in “–aceae.” Thus, any of the family names that did not already end in “–aceae” were changed to do so. Also, due to a recent re-examination of its traits, the whole Aceraceae family was merged into another family, the Sapindaceae. Thus, those of us who are not botanists and learned all of the older names when we were in school are having to try to remember both sets of names so we can “translate” from one to the other.

Copyright © 1997 by J. Stein Carter. All rights reserved.
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