Excerpts from Jim Conrad's
from the February 18, 2018 Newsletter issued from Rancho Regensis north of Valladolid, Yucatán, MÉXICO
VARIEGATED YOUNG LEAVES OF SYNGONIUM/ ARROWHEAD VINE
Here as the dry season is starting to get serious with its heat and longtime lack of rain, on the shaded, leaf-littered floor of older parts of the surrounding forest you see freshly emerging, attractively variegated leaves like those shown below:
You've probably seen similar foliage on shade-tolerant potted plants up north. When these leaves first emerged I couldn't imagine the plant's identity, because here I've seen no mature plant producing such leaves. Potted plants with such ornamentation, fleshy texture and shape usually are members of the Arum or Jack-in-the-pulpit Family, the Araceae, and I was pretty sure that our emerging leaves also belonged to that family, but still I drew a blank. The breakthrough came once the leaves had developed a little more, producing what's shown below:
The leaves lose their arrowhead shape and become deeply lobed and compound. Here we do have viny members of the Arum Family with compound leaves such as these, in the genus Syngonium. However, Syngonium vine leaves aren't the least varigated. The next discovery supporting my suspicion that this is a Syngonium came with the discovery of what's shown below:
The top ¾ of that image definitely shows leaves a Syngonium vine, and the lower ¼ shows much smaller leaves with arrowhead shapes and variegation. My finger poked into the soil followed the smaller leaves' stem downward until it connected with a much larger stem, which seemed to be the origin of the vine with larger leaves. Therefore, the fancy little leaves emerging nowadays are Syngonium leaves.
At this point in the quest for a solid ID, complications develop. We have two Syngonium species names here we could be dealing with, Syngonium angustatum and Syngonium podophyllum. Some authors regard Syngonium podophyllum as just a form of Syngonium angustatum, in which case our vine would be Syngonium angustatum. However, it seems that most specialists keep the two species apart. With the vegetative material we have here I can't say which it might be, and I'm not sure I could even with it. Therefore, I'll just call it Syngonium Vine.
Why does the vine feel like it needs to variegate its young leaves and not its older ones? It seems that it'd prefer having no variegation at all, since those white splotches must reduce the leaves photosynthetic capacity. Maybe young leaves benefit from the ornamentation because that provide "disruptive camouflage," which to a leaf-grazer's eye might cause the young leaves to appear less leaflike amid the forest floor's visual clutter.
from the April 24, 2016 Newsletter with notes from a visit to Lacanja Chansayab in the Lacandon Reserve, Chiapas, MÉXICO
A viny, high-climbing member of the Arum or Jack-in-the-pulpit Family, the Araceae, commonly seen in Chiapas's Lacandon Reserve, is the one shown above.
Notice that the big blades are attached to long, arcing petioles, and that the blades are compound, consisting of several leaflets, very unlike the above Monstera Vine. In the above picture, the cluster of fruiting structures in the center is what catches the eye, and a close-up of that is shown below:
The oval, red-turning things on erect stalks are not fruits but rather what can be called "fruiting spadices." You might recall that flowers in the Arum Family are very small and numerous, packed closely together on a vertical, finger-like structure known as a spadix, with male flowers at the spadix's top, and female ones at the bottom. The entire spadix is accompanied by a leafy "spathe," which partly or completely wraps around the spadix. On the Jack-in-the-pulpit flower, "Jack" is the spadix while the "pulpit" is the spathe.
In the picture, the male part and the part of the spathe wrapping around the male part have fallen off, leaving a scar at the top of the oval "fruiting spadices." The fleshy, red-turning coverings of the "fruiting spadices" are parts of the old spathes that formerly enclosed the female part, or bottom, of the flowering spadix. Inside the mature, red "fruiting spadices" at the right in the picture, the former ovaries now are mature fruits grown together into a fruit-like structure something like an ear of corn. Each "fruiting spadix" is actually a collection of many fruits, which are hidden inside the fruiting body.
This is SYNGONIUM ANGUSTATUM, a species fairly common in southern Mexico south to Costa Rica. It has no good English names so some aroid enthusiasts just to call it Syngonium Vine.
At Hacienda Chichen in north-central Yucatan the vine is planted and we've documented its leaf variation, aerial roots and flowers there, as shown at http://www.backyardnature.net/yucatan/syngonm.htm