Where When How — May/June 2017
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Native Flora A Botanical Calendar
B Naqqi Manco

EVEry PrOFESSION HAS INSIDE jOkES, and not being an office-oriented person, I’m quite sure I wouldn’t get the bulk of them. In botany, the inside jokes can be as every bit as strange as botanists themselves often are – and I like to think the stranger the plants that are involved, the stranger the humour.

A colleague of mine worked on a remote island in the South Pacific where it was difficult to measure the passing of days. She marked her days by focusing on different plant groups on different days of the week, saving her favourites for Fridays – favourites which happened to be the lowliest of the higher plants, mosses (which most people recognise) and liverworts (slightly more obscure). Together, these plants make up a section of botanical life collectively called the non-vascular plants, because they lack vascular tissue. I know, this is getting far too botanical, but stay with me.

Vascular tissue is the tubes in plants that carry sap and water around the plant – the veins, if you will. It is what allows trees to be able to pump hundreds of gallons of water up sometimes several hundred feet in the air, in complete silence. It is what drips the lovely juices that give us such products as latex, maple syrup, and quinine. But not all plants have vascular tissue.

The first terrestrial plants in history hadn’t yet evolved veins – their inner cores were filled with spongy material that allowed liquids to move about freely. They lost a lot of water to evaporation without being able to protect it inside sealed tunnels, and so they were often restricted in size and environment. Though in past eras, the atmosphere allowed some to get quite large, today’s worldwide climate keeps mosses and liverworts small and usually restricts them to damp, humid places.

While tropical rainforests, cloud forests, and temperate forests are often dripping in non-vascular plants, they’re decidedly uncommon in the dry tropics. Still, a few call the Turks & Caicos Islands home. They adapt to our harsh environment by being even smaller than their relatives. While most liverworts grow to about a centimetre wide, ours are less than 1/10 that size, growing on packed soil in open areas where they can unfurl and photosynthesize following rain showers. Afterward, they dry up and remain in a suspended animation until the next rain. Liverworts are so named because the shape of thallose liverworts resembles the outline of the human liver, and in Medieval times was thought to be a cure for liver diseases.

Mosses also grow in these dry places, encrusting not just tree bark but often the trunks of cacti. Instead of being soft cushions, our mosses are spikey crusts. Unfortunately, the identity of most of these species has never been confirmed in the Turks & Caicos Islands. Non-vascular plant identification is a challenge to botanists, who like to use flowers and fruit to identify species. Mosses and liverworts don’t have those reproductive structures, as they reproduce with spores, not seeds. Despite the difficulty in identifying these plants, we keep trying. We don’t yet have enough to dedicate a day of the week to them, but because the outdoor work environment of botanists demands dressing down every day, we don’t have a need for casual Fridays. I’ll happily keep working on these unusual plants on our non-vascular Fridays.