Excerpts from Jim Conrad's
NATURALIST Newsletter

from the July 30, 2017 Newsletter issued from Rancho Regensis north of Valladolid, Yucatán, MÉXICO
AIR PLANT BUDDING

Late last year as the dry season was getting underway, in November or so, in the dusty, crinkly forest along the trail from the rancho to the main road, I noticed a scraggly, thick-leafed plant shriveling up in the dryness and losing some of its leaves. I knew this plant, and knew that its leaves, with scallop-margined blades about the size of a hamburger, did something special. A leaf was collected, tucked into my pocket, and when I returned to the rancho the leaf was placed on some moist soil in a pot. In only three or four days, at the indentations between several of the blade margins' crenations, tiny, white rootlets formed, mantled with almost microscopic root hairs. These formed on the leaf's underside. Below, you can see a picture of the rootlets on the flipped-upside down leaf:

BRYOPHYLLUM PINNATUM, rootlets forming beneath blade

The leaf was carefully returned to its moist soil, the rootlets directed toward the soil, and in about a week little green sprouts appeared on the upper side of the leaf, from the same indentations. About three weeks later, the leaf appeared as shown below:

BRYOPHYLLUM PINNATUM, sprouts forming at blade's margin

Once these sprouts along the leaf's margin were about finger high and crowding one another -- the leaf itself now withered and decaying -- some of the sprouts were transplanted to a spot near the hut so I could have the fun of watching it grow, and have souvenirs of the hot, wickedly dry day I stuffed the mama-leaf into my pocket. Nowadays the plants are about knee high. Below, you can see one:

BRYOPHYLLUM PINNATUM, young plant

Something interesting about the young plants is that the first leaves to appear consist of just one blade on a petiole; they're "simple" leaves. But later on, they become "compound" leaves, consisting of three or five leaflets. Below, you can see a three-parted, or trifoliate, leaf -- its purplish petiole pointing toward the left:

BRYOPHYLLUM PINNATUM, trifoliate leaf

I knew this plant when I first saw it because it's a common houseplant, and because this species often is brought into biology classes to illustrate an example of "vegetative reproduction." In English is goes by many names, including Air Plant, Life Plant, Miracle Leaf, Floppers, Cathedral Bells, and Goethe Plant. (Goethe really liked it, talked about it a lot, and gave little sprouts to visitors, which I can do, too.) Unfortunately, none of those English names is much good, either because other unrelated plants share the same names, or their use is erratic. Up North, often Bromeliads are known as Air Plants. Anyway, the plant shown in our photos is BRYOPHYLLUM PINNATUM, native to Madagascar, but naturalized and "gone weedy" in much of the world's tropical and subtropical zones.

And now to undo some of the misleading statements made above: The items I've been calling leaves -- to keep from getting bogged down -- aren't really leaves. They're "phylloclades," which are stem branches, more or less flattened and functioning as and often looking like leaves. That explains how the Air Plant's "leaves" can produce new plants along their margins. They're not leaves at all, but rather stems branching and sprouting the way stems are supposed to. Christmas Cactuses consist of phylloclades.

When you see such juicy-looking plants with no spines, stinging hairs, or other obvious defenses, you wonder what's to keep herbivores from feeding on it. The answer is that they are toxic. Bryophyllum pinnatu contains compounds known as bufadienolide cardiac glycosides, capable of causing heart problems in grazing animals.

We've seen that when a plant is toxic, often in small doses it's also medicinal, and that's the case here, at least in traditional medicine. Though the Maya know nothing about it -- it wasn't in the Americas during the formation of the Maya pharmacopoeia -- in various places it's been used to treat hypertension, and its juice to cure kidney stones, though no scientific studies support these uses.