“If you reveal your secrets to the wind, you should not blame the wind for revealing them to the trees.” — Kahlil Gibran

Plants and air have a complex relationship. Plants exchange carbon dioxide and oxygen with the atmosphere, and strong winds can uproot trees, but the relationship some plants have with air is rooted even deeper.

Bee pollinating a flower.  photo by John F. Williams

While flowering plants reliant on animal pollination put a lot of energy into developing attractive flowers, wind-pollinated plants use their energy to create large quantities of pollen. Since the wind is less precise at transferring pollen than animals are, much of the pollen a wind-pollinated plant produces may never reach its intended target. The more pollen a plant produces, the more likely it is that some pollen will successfully land on a female flower or cone. Unfortunately, large amounts of pollen drifting through the air is a nightmare for people and animals with pollen allergies.

wind-pollinated species of the pnw

The Puget Sound region is home to many native plant species that rely on the wind for pollination, including grasses, Douglas fir (Pseudotsuga menziesii), Western red cedar (Thuja plicata), Garry oak (Quercus garryana), red alder (Alnus rubra), and beaked hazelnut (Corylus cornuta). Some plants, such as Sitka willow (Salix sitchensis), are pollinated by both wind and insects. English lavender (Lavandula angustifolia) is not native to the Salish Sea region, but it is loved by many local gardeners and bees, making it an excellent choice for pollinator gardens. Despite its allure to animal pollinators, English lavender can also be wind-pollinated.

what’s in the wind?

Air’s role in plant reproduction is not limited to pollination. Air movement is also important for seed dispersal (anemochory) for many plants, regardless of whether the plant was pollinated by wind (anemophily) or by animals (zoophily). Big-leaf maple (Acer macrophyllum) produces inconspicuous clusters of greenish-yellow flowers that are pollinated by insects. Each flower in the cluster, when pollinated, will develop into a winged seed called a samara.

While many plants develop winged seeds, big-leaf maple is one of the few species that produces winged seeds in pairs. As the seeds dry on the tree, the pair will split apart, and each seed will fall on its own. The shape of the wing allows the seed to spin like a helicopter rotor as it falls. This enables the seed to fall more slowly and to be moved by air currents. Without any wind, the seed would spin straight down to the ground, but even the slightest movement in the air will carry the seed away from its parent tree, and, hopefully, to an ideal spot for germination.

Dew on dandelion pappi. photo by John F. Williams

Hairy bittercress (Cardamine hirsuta), more commonly known as shotweed, is a non-native nuisance for many gardeners around the Salish Sea. Each seed inside a shotweed seed pod has a coil structure. As the seeds develop, the seed pod begins to swell and eventually splits along the line of weakness. As the pod splits open, the coils release and shoot the seeds away from the pod, and occasionally into the eye of an unlucky gardener. (Editor’s note: If you spot the invasive shotweed in your yard or garden, please contact the Noxious Weed Control Board who will help you eliminate it.)

there’s a fungus amungus

Like plants, some fungi species utilize the wind for reproduction. However, fungal reproduction is not the same as plant pollination. Spores may seem similar to pollen, but pollen is made up of male gametes (cells) which must fuse with a female gamete to cause fertilization. A fungal spore is a single cell that can germinate on its own. While pollen must transfer from the male structure to the female structure, fungal spores simply need to land in a suitable location.

Many species of fungi rely on air to disperse their spores; the most iconic may be the puffballs. Puffballs are a group of fungi that emit clouds of spores into the air. As the fruiting body, called the peridium, emerges from the ground, the structure is solid, but as it matures, the inside hollows out and is filled with powdery spores. Each spore is connected to the peridium by a tube under tension. When rain, an animal, or the wind disturbs the peridium, the tension is released, and the spores are ejected through an opening in the top of the structure in what looks like a puff of smoke.

Puffball mushroom full of spores. photo by John F. Williams

While puffballs keep their spores inside their fruiting body, gilled mushrooms develop their spores externally. These external spores can be released passively by wind or actively catapulted off the gills. Once in the air, the spores are left to the whim of the wind.

Studies on fungi have shown that because of the microscopic size of the spores, air drag quickly slows them down and they do not travel far. To increase their travel distances, some species of fungi have adapted by changing the shape of their spores to be more aerodynamic. Another adaption is to release a large quantity of spores at once. When a mass of spores is released at the same time, it generates air flow that helps carry more spores farther away from the fruiting body. One study found that spores that were released together traveled up to 20 times farther than spores that were ejected individually.

blowing in the winds of climate change

The relationship air has with plants and fungi is ancient, and the development path of anemophily (wind pollination) and anemochory (seed dispersal) is not the same for all species. Some plants, predominantly gymnosperms, relied on the wind from the start. Others, such as the majority of angiosperms, adapted over time to wind pollination as a response to low numbers of pollinators.

The earth is not static and changes in climate have impacts on the species that live here. It can be easy to notice how climate change affects pollinators and their plant pals, but increases in temperature also affect plant fertility. For example, higher temperatures can reduce the amount of pollen plants produce, can kill pollen, or prevent pollen from being released. Changes in rain and air moisture can also reduce how far airborne pollen, seeds, and spores will travel.

As the climate changes, some animals can migrate to suitable conditions. Plants and fungi, however, especially those reliant on the wind for seed and spore dispersal, are only able to travel where the air allows. If the wind blows a seed into inhospitable territory, that seed will not grow. If too many seeds or spores are unable to grow, species will die out.

Humans can choose to become stewards of the earth and help wind-reliant species to travel to new suitable locations. Gardeners can opt to plant a diverse mix of species in their gardens. This allows native plants access to areas they may not have been able to reach on their own. When planting trees, consider how the climate may be different once the tree is mature and choose a tree that will be better suited for future conditions.

Although climate change may cause some plant, fungi, and animal species to go extinct, others have the potential to adapt. In the past, when animal pollinators were not abundant, some plants evolved to be pollinated by the wind. While not all will survive, there is hope that some resilient plants will take advantage of the ever-present air and find a way to live on in a new climate.

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