November 27, 2011 @ 9:14 pm
Haworthia tessellata is one of my favorite plants. At least that’s what I tell people. One friend has complained that I say that about so many plants that it can’t possibly be true.
The latin name tessellata comes from the tiled pattern in the leaf faces. Attractive, yes, but the bigger truth about these odd, waxy leaf faces is this: they evolved to be natural windows. Many Haworthia have adapted this way. Sunlight enters the plant body through these translucent windows and is converted into energy by many layers of chlorophyll-rich cells.
This is especially useful in the arid climates where Haworthia tessellata makes its living; the primary photosynthesis tissues are not exposed to the drying elements.
Leaves with window tops are described as fenestrate, from the Latin for window: fenestra.
What’s more, like many succulents, Haworthia tessellata can photosynthesize using Crassulacean Acid Metabolism (CAM). During CAM photosynthesis, the plant opens its stomata only during the cool of the night. It “inhales” in carbon dioxide and stores it in its thick, succulent tissues (while “exhaling” oxygen). During the heat of the day, the carbon dioxide stored deep in the plant can be used in photosynthesis because sunlight passes through the leaf windows, deep into the center of each leaf.
Haworthia tessellata (synonym Haworthia venosa ssp tessellata) is found many places in Southern Africa, especially central South Africa, also extending northward into Namibia. This stemless plant sends underground stolons up to 14cm (5.5 inches) away from the mother plant. This vegetative reproduction results in a mat of plants, and also makes it easier to propagate of select clones such as those pictured here.
Breuer, Ingo. (2010). The Genus Haworthia – Book 1. Alsterworthia International. Softcover, Illustrated, 86 pages. ISBN 13: 9780955272677.
Breuer classifies Haworthia tessellata as a separate species, disagreeing with Bayer, who calls it a subspecies of Haworthia venosa.
Bayer, Bruce. (2003). Haworthia Update – Volume 1. Umdaus Press. Hardcover, Illustrated, 64 pages. ISBN 10: 1919766219
Court, Doreen. (Third Edition, 2010). Succulent Flora of Southern Africa. Cape Town, South Africa: Struik Publishers. ISBN-10: 1770075879. ISBN-13: 978-1770075870.
Pilbeam, John. (1983, Hardcover) Haworthia and Astroloba. ISBN-10: 0917304659. ISBN-13: 9780917304651