There are several types of leaf vernation when a new leaf first emerges. Vernation is simply the way a new leaf blade is rolled or folded as it begins to emerge from the cataphyll which many people call a "sheath". Although there are several forms of vernation in aroids the most common type is known as convolute vernation which describes the edges of a newly unfurling leaf blade which have both margins (edges) curled inward wrapping around each other. This is observed when the new blade emerges from the cataphyll and the wrapping of one margin is rolled over the other. The mechanism makes the emerging leaf present itself as a tube. The second is known as involute vernation and is observed when a newly developing leaf emerges from the cataphyll when both margins (edges) on opposing sides of the leaf blade are rolled forming two inward facing tubes that meet at the midrib of the leaf. This type is not as common as convolute vernation. Technically supervolute vernation is the same as convolute vernation. . I have been working for weeks to complete an article for the next issue of Aroideana (the journal of the International Aroid Society) to be published in August. That article attempts to make many of the terms used in scientific literature easy for a collector to understand and use. One of the most difficult definitions to write was the one for supervolute vernation since a complete definition did not exist in any of the scientific texts or journals I own. I couldn't even find a definition on the internet and the definition I found on the internet for "supervolute" was impossible to understand. Look it up and see if you can figure out what they are trying to say! Finally my friend Leland Miyano sent a photo of a newly emerging leaf of Anthurium hookeri and the definition Dr. Tom Croat helped to clarify suddenly became crystal clear. Until I received this photo I had no real idea what supervolute vernation really meant. supervolute vernation Possessing a convolute arrangement in the folding or arrangement of a newly emerging leaf blade with one margin (edge) of the newly blade emerging rolled inward toward the midrib and the opposite margin rolled around the midrib as well as the remainder of the leaf in a manner similar to the coiled whorl at the end of a conch shell. My thanks to Leland for the photo!
After consulting with Dr. Croat and botanist Pete Boyce I have changed the definitions slightly in hopes this will better explain the differences in the forms of vernation common to aroids. After some weeks of correspondence Dr. Croat has now stated there is no real difference in supervolute and convolute vernation. Basically, they are synonymous which means there is no real difference. convolute vernation Used to describe the edges of a newly unfurling leaf blade which has both margins (edges) curled inward as when when one part is wholly rolled up in another part. Observed when the new blade emerges from the cataphyll and the wrapping of one margin is rolled over the other presenting itself as a tube. Convolute vernation occurs when several leaves spiral with the next leaf in a module enclosed within the current leaf. involute vernation Observed when a newly developing leaf emerges from the cataphyll with both margins (edges) on opposing sides of the leaf blade are rolled forming two inward facing tubes that meet at the midrib of the leaf. Aroids in the genus Lagenandra, Anthurium section Pachyneurium as well as species in the genus Amorphophallus exhibit involute vernation. supervolute vernation Possessing a convolute arrangement in the folding of a newly emerging leaf blade with one margin (edge) of the new blade emerging rolled inward toward the midrib and the opposite margin rolled around the midrib as well as the remainder of the leaf in a manner similar to the coiled whorl or spiral at the end of a conch shell. Technically the same as convolute vernation.
