Naturespeak A naturalist's view of the world

March 23, 2014

Nickernuts and Piddocks

Filed under: Uncategorized — wykes @ 9:42 am

This will be – I promise – the next to last regurgitation of my trip to the Gulf Coast of Florida. Like a mother bird coughing up something for her young, I perform this task for your own good. I also perform this task because so much of what I saw there was “new” to me and tingled my naturalist senses. What comes out may not fully resemble the original product but it is nutritious and, since you have full control as to whether you read this stuff or not, I will continue until somebody stuffs a Nickernut Pod down my pants.

I am fascinated with regional names and seed pods. Tucked among the White Mangroves of the DeSoto National Memorial site at the mouth of Tampa Bay are plants which simultaneously satisfy both categories. I am referring to the Gray Nickernut vines. Draped innocently on the low mangrove branches, these woody vines are armed with thorns and double compound leaves.  They are in the pea family. Clusters of bristly dark brown (or light green immature) seed pods are suspended at regular intervals along the vines.

Like a coin purse from hell, mature pod spits open to reveal a cargo of large smooth seeds. The pods are about three inches long and just big enough to contain three one-inch diameter seeds. Because of their resemblance to clay marbles, both in color and texture, vines in this family came to be known as marble plants – using the Dutch word for marble which is “knikker.” Combine the fact that these particular “nuts” are gray and you have the species name of Gray Nickernut.  I’m not exactly sure why a Dutch term was used, but am glad for it. There are dozens of Knickernut species throughout the tropical regions of the planet and it is possible they were first named in the Dutch East Indies!  Hey, call me nuts but that might explain things (the name – not my being a nut).


Eventually the natural drying process forces the pods to peel wide open and drop their seeds to the sandy ground. Many of the seeds will be flushed away by rising tide waters and travel for thousands of miles on the open ocean currents. Because of this ability to withstand long salt water exposure Nickernut seeds are collectively called Sea Beans. The seeds wash up on distant shores and take root if not collected by human hands. The Gray Nickernuts are rather bland, but other species in the group are brightly colored and all are frequently stung together to make attractive Sea Bean necklaces.

Personally I would never be caught dead wearing a Sea Bean necklace, but might try out another popular use of Nickernut seeds (especially since I am now the proud owner of 4 gray sea beans). Apparently in some parts of the Caribbean mischievous children will briskly rub a Nickernut back and forth on their clothing in order to heat it up and then touch the scorching nut onto the flesh of an unsuspecting victim. Now that’s good old homemade fun. Imagine how unsuspecting my northern friends will be when I burn them with one of my tropical nuts. Sure those Caribbean folks are always on the watch for red-hot Nickernuts, but how many Michiganders would suspect a Nickernut attack!

As far as I know, Caribbean children do not perform nasty tricks with Piddock clams. These burrowing mussels dig tunnels into wood or rock and are near impossible to extract. One sizable tree limb lying on the ground adjacent to one of the Knickernut vines (I just had to say Nickernut once more) was riddled with clam holes. Now dried and exposed, each woody hole contained the shelly remains of the single Wedge Piddock clam that excavated it. The gapping maws of several dozen dead clams stare out at you.

When alive, the Piddock barely fits its shell. A pair of siphons sticks out the “back” end and a fleshy mantle and foot out the other. They employ a combination of methods when drilling into hard substrates (some species can actually burrow into solid rock). The leading edge of the shell has a rasp- like surface which acts to scrape away at the sides of the burrow while the mantle (the skin folds which contain the living animal within the shell) exude a digestive chemical to soften the substrate.


Their burrows are perfectly cylindrical and about one inch deep – just enough to enclose he animal and allow for it to suck in micro-contents through its siphon. The shell itself is quite thin, however, and the animal requires the protection of a burrow. Unfortunately this attraction to floating wood subjects the colony to the whims of waves and wind. Once cast up high on a beach they will wither and die in the scorching sun.

Here in the north we ask whether a tree falling in the forest makes a noise if it is not heard. I submit that Florideans can now ask if a colony of dying Piddock Clams screams if no one is there to hear them!

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