Nothing says late summer quite like the blooming of the goldenrods. These conspicuous members of the aster family get a bad rap because many folks blame them for causing hay fever. This is simply not true! In this video we take a closer look at a small handful of goldenrods as a way of celebrating this ecologically important group.
Music by: Artist: Ampacity
Track: Encounter One
Photo by Nedra licensed under CC BY-NC-SA 2.0
Fall is such a great time to take advantage of some awesome deals at your local nursery. Plants that have gone out of bloom or are in the process of going dormant always seem to have a lower price tag on them. What's more, fall is the best time, at least in the temperate zones, to plant most things. However, a fall stroll around a nursery or garden center isn't without floral beauty. One group of plants that are exceptionally beautiful at this time of the year are the toad lilies.
Native to parts of China, Japan, the Himalayas, Formosa, and the Philippines, the genus Tricyrtis is growing in popularity as a horticultural curiosity. It's not hard to believe once the true beauty of this genus is realized. In the wild, these plants are denizens of shady forest hillsides and are often encountered on wet slopes. Being a member of the lily family, the floral parts of these plants are arranged in multiples of three. Genetic analysis puts this genus into the same group as Calochortus lilies and indeed, they do share some superficial similarities.
Photo by dbarronoss licensed under CC BY-NC-ND 2.0
The flowers are the real selling points of this genus. They kind of look like a cross between a lily and a passion flower. The name toad lily comes from the speckled appearance of the leaves and petals. That is by and large the only toad-like qualities these plants have other than preferring moisture of course. There has been a lot of debate over what may pollinate the flowers. It is believed that at least some species such as Tricyrtis nana reproduce mainly via self-fertilization whereas others seem to attract mainly bumblebees.
Fall is here and the asters are out in force. Their floral displays are some of the last we will see before the first fall frost takes its toll. Their beauty is something of legend and I could sit in a field and stare at them for hours. In doing so, an interesting pattern becomes apparent. Have you ever noticed that the disc flowers of the many aster species gradually turn from yellow to red? Whereas this certainly correlates with age, there must be some sort of evolutionary reason for this.
Indeed, there is. If you sat and watched as bees hurriedly dashed from plant to plant, you may notice that they seem to prefer flowers with yellow discs over those with red. The plot thickens. What about these different colored discs makes them more or less appealing to bees desperately in need of fuel? The answer is pollen.
A closer observation would reveal that yellow disks contain more pollen than those with red discs. Of course, this does relate to age. Flowers with red discs are older and have already had most of their pollen removed. In this way, the color change seems to be signaling that the older flowers are not worth visiting. Certainly the bees notice this. But why go through the trouble of keeping spent flowers? Why not speed up senescence and pour that extra energy into seed production?
Well, its all about cues. Bees being the epitome of search image foragers are more likely to visit plants with larger floral displays. By retaining these old, spent flowers, the asters are maintaining a larger sign post that ensures continued pollinator visitation and thus increases their chances of cross pollination. The bees simply learn over time to ignore the red disc flowers once they have landed. In this way, they maximize their benefit as well.
Further Reading: [1]