An Excerpt from Jim Conrad's
Naturalist Newsletter

from the January 16, 2011 Newsletter issued from Hacienda Chichen Resort beside Chichén Itzá Ruins, central Yucatán, MÉXICO
INCH PLANT

Inch Plant, CALLISIA REPENSBack at Hacienda Chichen I went to check on the compost piles where fallen leaves end up. In heavy shade at the base of a Cedro tree there grew the fragile-looking little mat-forming herb issuing ankle-high flower spikes shown at the right.

The plant fascinated me because its semi-succulent leaves had parallel veins like grass blades, and their bases formed cylindrical sheathes around the stems, just like those of dayflowers, genus Commelina. Also, flower clusters were subtended by leafy bracts just as with the dayflowers. However, these blossoms lacked the conspicuous three petals so typical of dayflowers. This was something else, another variation on the theme of the Dayflower Family, the Commelinaceae, one I'd never experienced.

This is a native tropical American plant now growing throughout the world's tropics and beyond because it's often planted to form lush mats in gardens, to dangle prettily over pot sides, to hang from hanging baskets, and it often escapes into the wild. It's CALLISIA REPENS and because of its wide occurrence it goes by many English names, including Inch Plant, Bolivian Jew, Turtle Vine and Chain Plant.

Nearly all photos of Inch Plant on the Internet show sterile plants. It's the mat-forming, dangling-over-the-sides herbage people want to see, not the piddling little flowers. Still, those flowers are interesting and pretty by their own right, as seen below:

Inch Plant, CALLISIA REPENS, bisexual flowers

In that picture a cluster of flowers arises from the juncture of the stem and a leaflike bract. Three flowers can be made out, each one issuing five stamens and a single style tipped with a white, powder-puff-like stigma. Notice that each anther is composed of two baglike cells that later will split open to release pollen. The two cells are connected by tissue expanded above into a very unusual, conspicuous, white, sail-like flap. I'm guessing that the flap catches the wind and shakes the anthers to dislodge polen.

Callisia repens produces two kinds of flowers. The ones shown are bisexual -- bearing both sexes -- but sometimes pure female ones are produced, the stamens completely absent.