Though “homage” seems a rather uppity word to me, if ever a plant deserved one it is the elegant understory shrub Lindera benzoin, also known as Spicebush. And if you haven’t noticed it before you may at this season, when Lindera’s leaves illuminate lowland forests with a lemon-to-gold glow.
Here in the Ohio River Valley, chilly overnight temperatures are making for an especially colorful fall. I’d been away from this forest for a few days, and coming down the trail just at dusk last week, I was met with a remarkable sight. Hundreds of Spicebush lit up the lower slopes like pale gold fire, with many more still to turn.
Especially gratifying (big thank-you to the Forest stewards!) is the fact that a great number of these had been planted as tiny bare roots over the previous eight years, and were now coming into their young adulthood.
The last lingering berries are now getting stripped off by flocks of Robins, who actually regurgitate the large seed. It’s also gratifying to see the Robins eating Spicebush instead of invasive Bush honeysuckle berries, since they appear to be the main seed dispersers in this forest.
Under favorable growing conditions, female Spicebush will bear fruit when they’re about five years old. More sun equals more berries, though the plant thrives best in light shade. In the image below, a male and female Spicebush grow side by side, as is often the case in nature. Sex ratios come out relatively balanced, though I have no idea how this occurs.
It’s possible to determine the gender of mature plants at most seasons – female plants have berries present from May through Nov. at least, while male plants are now budding with next spring’s flowers. When both are blooming together in early spring, male plants produce far more of their pollen-bearing flowers. This makes sense, since the energetic demands are greater for the berry-ripening female plants.
The genus Lindera is considered a “relict” in Eastern North America, with only three species compared to the 80+ species found in Asia. Lindera is yet another character in one of my favorite botanical true stories: the Eastern Asian–Eastern North American Floristic Disjunction. There were formerly many more species of Lindera here as well, but ancient climate change, geographic isolation, and modern fragmentation finished off most of them. Of the three remaining Lindera species in North America, two are very rare, hanging on in small and isolated populations. But Spicebush has triumphed as a relatively adaptable generalist, suited to our times. Though climate change may present new challenges, Spicebush has survived both warmer and cooler periods. Currently a rare plant in Maine, it will expand its range northward in the coming centuries.
It’s quite interesting (for a plant geek anyway!) to compare and contrast the Asian and North American species. For example, the Japanese spicebush Lindera obtusiloba, bears a remarkable resemblance to our native Sassafras Sassafras albidum. Both are in the Laurel family, and both have leaves with three different lobe variations. The berries of Japanese spicebush look much more like those of Sassafras than our native Spicebush. What we call species are just a point in time, the putty of natural selection!
Did I mention the elegance of Spicebush? The plant in the image above lived its early life deep in a thicket of Bush honeysuckle, and had to stretch and lean to receive any light. As an understory-adapted shrub, Spicebush has a unique architecture; with abundant sunlight it can be rather compact and upright, but in lower light the branches, twigs and leaves orient themselves in a spreading solar capture array. Branches fan out sideways in a graceful, curving search; so flexible they often bend rather than break if a tree falls on them.
Though I won’t delve deep into Spicebush’s unique phytochemicals in this post, suffice to say that understory plants often possess noxious or toxic compounds for the purpose of deterring browsers like deer. These compounds are of interest to medical researchers in particular since they may have potential uses in developing new drugs. But Spicebush garners plenty of ecological study as well. When writing my posts, I like to parse through research studies and plunder/interpret what I find useful. I like to think of my blog as something of a bridge between these often obtusely worded studies and my blog readers.
The titles alone are fascinating, since they state clearly the purpose of the research. Listed below are some of the studies I browsed while writing this post – though I did not use much of the information in them, it will likely turn up in a future post:
Bisabolane sesquiterpenes from the leaves of Lindera benzoin reduce prostaglandin E2 formation in A549 cells
Chemical composition of the leaf essential oil of Lindera benzoin growing in North Alabama
The effect of microhabitat, spatial distribution, and display size on dispersal of Lindera benzoin by avian frugivores
A model of patch dynamics, seed dispersal, and sex ratio in the dioecious shrub Lindera benzoin (Lauraceae)
As with every other aspect of the natural world, there is no end to what one can learn about Lindera benzoin. Though I have written much about Spicebush, I hope to find ever new ways to extoll its many virtues!