Haworthia tessellata 'Neat' shooting a bloom stalk. Can you see the windows in the leaf tops?

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.

Haworthia limifolia, a close relative of H tessellata but lacking obvious windows in its leaves. It resembles opaque, molded plastic rather than translucent, carved wax.

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.

Haworthia tessellata 'Fang', a select clone named for the teeth and tubercles on the leaf undersides.

Leaves with window tops are described as fenestrate, from the Latin for window: fenestra.

Haworthia tessellata 'Super Tessellata', a beautiful, select clone

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.

See Also

Convergent Evolution in Succulent Desert Plants: Comparing Haworthia and Aloe (Africa) With Agave (America)

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.

Also posted at The Mad Professah Lectures

Adenia stylosa, photo by Mr Sentient Meat of his plant

Okay, maybe Adenia stylosa isn’t truly evil. But its heart-shaped purplish leaves are the color of a deep wound. They do have dark red veins. And consider the stem… the gnarled, waxy, green, enlarged trunk or caudex. To me it looks like a living version of a melted candle destined for a Satanic ritual. In fact this plant’s common name is reportedly “Candlestick Plant”. That’s fitting, as far as it goes. It does lack a bit of punch, a bit of drama. I think we should all start calling it “Satan’s Candle”. Who will be the wiser? Common names don’t really matter anyway. Whatever you call it, it’s a plant straight out of Charles Addams or Edward Gorey.

Adenia stylosa "Candlestick Plant" photo by Michael Malice of his plant

Now to the anatomy of evil… or at least the secrets behind Adenia stylosa‘s macabre appearance. Its above-ground tuber… okay, “tuber” doesn’t sound very evil… this caudex even has vaguely anatomical “hips”: actually a distinctly swollen hypocotyl, the portion of the stem below where its cotyledons were attached and fell away in the seedling’s infancy. The leaves are dark and attractive, varying between individuals as shown in this picture by Olaf Pronk.

Adenia stylosa leaves vary greatly between individuals

Adenia stylosa was known previously as a subspecies of Adenia firingalavensis or Adenia epigea but is now considered a separate species. It lives in Northern Madagascar, in Ankarana National Park among other places.

One last thing. If you have the pleasure of meeting Adenia stylosa in person, don’t be tempted to eat it. Not even that “above-ground tuber”. All parts of this plant are poisonous. And that’s… well… maybe just a little bit evil.

Huntington Botanical Garden’s introduction of related Adenia epigea

Also posted at MadProfessah.com

Dorstenia lavrani, too young to be sexually active (no hypanthodia),  photo by Sentient Meat

After you read about the bizarre sex life of figs and fig wasps, you can’t really say that the genus Dorstenia is much stranger than other members of the fig family, Moraceae. Still, you can’t help but notice the bizarre blooms of Dorstenia called hypanthodia. They look like psychedelic set decorations from the original Star Trek.

Photo of Dorstenia hybrid hypanthodium by Josiah Hartzell Ripe seeds are ejected and may land far from the mother plant

Dorstenia has about 100 species. Most are monoecious with bisexual hypanthodia, but today’s focus, Dorstenia lavrani, is dioecious, meaning some plants are male and bear pollen, while others are female and bear ovaries and later seeds. My young plant has not shown any hypanthodia yet, so I don’t know its sex. I hope it’s female.

Same Dorstenia lavrani pictured above

Legendary plant explorer John Lavranos discovered this plant variety in 1973, but it was circulated among collectors as a form of Dorstenia foetida — a fascinating but much more common plant — identified only by its locality, Taba’a Gap or Taba’a Gorge. It was finally described as a distinct species and named Dorstenia lavrani only in 2008.

Beautiful, prizewinning plant about 14 inches high (not counting the Sideshow Bob topknot) Plant from Yvonne Hemenway, iPhone snapshot by Sentient Meat

Dorstenia lavrani mesmerizes me with its pale, wax-like skin and its helix of leaf scars running up and down each stem. Well grown plants are visually striking, magnetic to growers and plant show judges alike. Apparently animals also find it irresistible — it was the first plant to be devoured off my deck. The small plant in these photos is its replacement. The first day, only a nibble was missing. The next day, all that remained was a crater in the soil.

Breeding female Dorstenia lavrani at Mike and Maureen Massara’s growing grounds photo by Bruce Brethauer, Columbus Cactus Club