A Shout Out to Western Skunk Cabbage

Photo by Martin Bravenboer licensed under CC BY-ND 2.0.

We all have our biases and one of my biggest botanical bias is that I often think of plants from eastern North America before my mind heads further west. I can’t really fault myself for it because so many of my early plant experiences occurred east of the Mississippi. I want to remedy this a bit today by drawing your attention to a wonderful aroid who frequently gets overshadowed by its eastern cousin.

I am of course talking about western skunk cabbage (Lysichiton americanus). This incredibly beautiful plant enjoys a distribution that ranges from southern Alaska to central California and west into Wyoming and Montana. Like its eastern cousin, western skunk cabbage was awarded its common name thanks to the pungent odor it produces. Its blooming period ranges from March into May depending on where they are growing and the inflorescence is truly something to write home about.

The spadix of western skunk cabbage complete with a tiny rove beetle pollinator. Photo by Walter Siegmund lincensed under CC BY-SA 3.0

Emerging from the base of the plant is a bright yellow structure called a spathe. The spathe envelopes the actual flowering parts, a phallic-looking structure covered in flowers called a spadix. The spadix emits various volatile compounds that function as pollinator attractants. However, whereas many would suggest flies are the preferred pollinator, research indicates that a tiny species of rove beetle called Pelecomalium testaceum takes up the bulk of pollination duties for western skunk cabbage throughout much of its range.

The volatile compounds aren’t there to trick the beetles into thinking they are getting some sort of reward. The plant does actually reward the rove beetles with pollen to eat and relatively safe place to mate. We call these types of signals “honest signals” as they act as an honest calling card that signifies rewards are to be had.

A closer look at a Pelecomalium rove beetle. Not sure which species. Photo by Judy Gallagher licensed under CC BY 2.0

Unfortunately, the beauty of western skunk cabbage has seen it enter into novelty garden collections in other temperate regions of the world. In northern Europe, western skunk cabbage has escaped the confines of the garden and is now considered an invasive species in wetlands of that region. Take care to choose you garden plants wisely. Always plant native plants when the option presents itself.

Photo Credits: [1] [2] [3]

Further Reading: [1] [2]

The Flowering Rush

Photo by Quite Adept licensed under CC BY-NC-ND 2.0

Say the words "flowering rush" and many will picture some grass-like, pond vegetation. However, the plant I am talking about today is not a rush at all. Known scientifically as Butomus umbellatus, the flowering rush superficially resembles a patch of true rushes, especially when not in flower. However, it is actually quite a unique species and the sole member of the family Butomaceae. Native to parts of Europe and Asia, this beautiful aquatic plant can now be found invading wetlands throughout northern North America.

Growing quite tall and producing an umbel of beautiful pink flowers, it is no wonder that this plant came to North America as a horticultural curiosity. Its overall appearance suggests a relationship with the genus Allium but genetic analysis puts it somewhere near the water plantains - Alismataceae. The interesting thing about this plant is that here in North America, individual populations exhibit either diploid or triploid chromosome counts.

Photo by Christian Fischer licensed under CC BY-SA 3.0

This is most likely a function of its horticultural past. Many commonly grown garden species have been selected for polyploidy in their chromosomes. Polyploid plants are often larger and more hardy than their diploid relatives, mostly due to the extra genetic material they harbor. It has been noted that there seems to be some reproductive differences between diploid and triploid flowering rush populations as a result. Diploids are more likely to reproduce sexually via seeds whereas triploids are usually sterile and reproduce vegetatively. Triploids are also less commonly found as escapees but they are more widely distributed than diploids. This is likely due to the fact that triploids are more commonly planted in gardens.

Whereas it seems that there is plenty of areas where people disagree on the invasive species issue, one thing we must keep in mind is that, no matter where you stand, biological invasions are one of the largest natural experiments this world has ever seen. We mustn't waste any opportunity to learn from these invasions and to gather as much data as we possibly can. Species like flowering rush offer us insights into how and why some species become invasive while others do not. The more we know, the better we can learn from the mistakes of the past.

Photo Credit: [1] [2]

Further Reading: [1] [2] [3] [4] [5] [6]

Do You Smell Skunk?

Do you smell that?

All around northeastern North America, a strange smell is starting to hang in the air. The skunky odor could easily be mistaken for an actual skunk but it isn't quite that strong. Some say garlic is a more apt description. If you are in a wet area you may notice small chimneys in the snow or what looks like a red and yellow parrot beak poking up from the ground. The smell gets stronger as you bend down to get a closer look. What you are seeing is Symplocarpus foetidus, better known as eastern skunk cabbage.

Skunk cabbage is a true spring wildflower. It is also one of those small groups of plants that can generate their own heat. This aroid can literally melt its way through the snow cover. Skunk cabbage hails from the same family of plants as the titan arum, Araceae. The inflorescence emerges in early spring, oten before the snow (if there is any) has had a chance to melt. Using heat generated via a unique form of metabolic activity, the inflorescence can reach temperatures of 15-25°C (59-77°F).

So, why the heat and smell? Well, if you like to bloom before the snow melts, you better hope you can at least melt through some of it. In deeper areas, skunk cabbage flowers create chimneys in the snow, which helps channel the scent up into the air. Though it may seem surprising, there are in fact insects out and about during the early days of spring. The smell attracts pollinators such as carrion flies and gnats. The heat also aids in volatilizing the odor, thus causing it to spread out farther. By blooming this early, skunk cabbage assures that its flowers get a majority of the attention.

After flowering is finished, the plant then throws up its large, green, elephant ear leaves. They are unmistakable. As the plant continues to grow throughout the season, its roots contract into the soil, digging the plant deeper and deeper. In effect, skunk cabbage grows down, not up. This is advantageous if you live in an area prone to flooding. The deeper you go, the harder it is to get pulled out.

I love this plant. It is wonderful to see its blooms poking up from underneath the snow. After so many months of drab colors and short days, this harbinger of spring is a breath of fresh, albeit stinky, air.

Further Reading: [1] [2] [3] [4] [5]