The Well-Whip

After a million and a half years, wellstalks have cemented their place as Apterra's most successful subgroup of the desert-grasses, being found in large numbers across all of the planet's arid regions. Most other xerophytes are in a state of decline as a result, and competition within the Calorhiza genus itself is intense. With the expansion of the ten-year desert, some regions now don't receive a drop of rain for several decades at a time. In response, the local wellstalks have gone to extremes to survive, culminating in the evolution of the Well-Whip (C. monophyllum). This species' defining feature is its odd method of growth. 

Like the seabaskets, its blades have adapted to grow continuously and indeterminately, increasing in length from their base as the plant ages. Uniquely, though, the well-whip has entirely foregone the production of additional blades and stems, relying instead on a single ever-growing leaf for its entire adult life. This is an energy-conserving measure, as it requires fewer calories than creating new foliage. At its end, the blade frays as it gradually rots away; if it decays faster than it grows, the plant will slowly die. Because it's a drought-adapted plant, the well-whip's leaves are especially susceptible to rotting if they come in contact with moist soil, a serious danger during harsh desert rainstorms. To prevent this, the long, straight blade is supported by a thick rhizome that protrudes a few centimeters above the sand.

In dry periods, the well-whip grows at a snail's pace, adding no more than half a centimeter of length each year. It can cling to life in this fashion for many seasons, awaiting the irregular desert rains. As a wellstalk, it can access buried aquifers, but the scant water it finds deep underground is rarely enough to support anything more than this slow-growing, semi-dormant lifestyle. When rain finally arrives, its metabolism springs into action. With luck, it will have stored a decent supply of energy in its underground stem over the years, which it taps into as it undergoes a burst of growth. Its leaf may double in size during this brief period, while a tall inflorescence quickly emerges from the axil and produces hundreds of grains in a matter of days. 

The well-whip is a very new species, having diverged from the rest of its genus only about 150,000 years ago. By now, it's found not only in the ten-year desert, but is quickly conquering similar habitats around the world. Some local varieties are even beginning to show adaptations that allow them to survive in Apterra's growing cold deserts, an ability that's sure to serve them well as the ice continues to advance.