Trop picks: Ferns

For your New Year's Eve feast this year, consider foregoing the usual floral centerpiece in favor of one made with ferns. These supporting actors have given us much to be thankful for in this year of the haze.

Often found growing on the trunks of old oil palms, their joint cooling effect made temperatures bearable on those days when the PSI was well above the 200 mark.

In fact, why not go the whole hog, recreating a small ecosystem, like our friends at Moss and Rose have done?

In the arrangement above, they have combined the bird's nest fern (Asplenium nidus) and the rabbit's foot fern (Davallia denticulata, named after the Anglo-Swiss botanist Edmund Davall, but its vernacular name arises from the fact that its rhizome or stem has furry dark brown scales, resembling a rabbit's foot).

The two are also neighbors in nature, where the spores of the rabbit's foot often start life in a nest of bird's nest ferns, eventually creeping out and growing independently of the nest.

The spores, if you're wondering, are the means by which ferns reproduce, and not seeds. It took a long time before the modern world figured that one out. Until then, people thought, rather fancifully, that ferns had invisible seeds and that these seeds, as oft quoted from Shakespeare (Henry IV, Act 2, Scene 1), gave one the power to become invisible, provided they were able to catch this elusive fairy dust. And it does feel like dust when you run your fingers along the underside of a fern, except that's actually the spores you're touching. For a time, this was mistaken for pollen.

But then, one day in 1794, a British surgeon stationed in Jamaica noticed that after the rains, quantities of ferns emerged from freshly disturbed soil. Curious, he sprinkled some fern dust in a flower pot and soon discovered the development of young fronds, convincing him he'd found the elusive fern seeds.

It took the botanists at Kew, however to figure out the vaguely scatological reproductive workings of ferns. Spores are stored within a structure called a sporangium. They are expelled from the sporangium following the puckering of a specialized ring of cells, known as the annulus.

Thus released, if the spores land somewhere suitable, they will grow into small, heart-shaped structures called gametophytes. These, in turn, produce both an egg and sperm. The sperm needs to swim through water to get to the egg, which is why ferns do better in wetter environments. When sperm and egg come together, a whole new fern plant is born, and the cycle repeats.

Clearly, there ain't nothing unnatural about annul.

Sources:

Sue Olsen in Encyclopedia of Garden Ferns, 2007.

David L. Jones, Encyclopedia of Ferns, 1995.