All Maduro is not created equally. Perhaps American Maduro is made from Broadleaf, but not all Maduro comes from the US. The Maduro I sell is not a Broadleaf type, it's not at all a "thick" leaf and it is not stalk harvested. San Andres wrapper could be a Broadleaf type, but I'm not sure, but San Andres isn't a Maduro.
Maduro is just a descriptive word for a dark wrapper, not any specific tobacco varietal. It can be made from many types. Actually, there are few types that can't be made maduro. Conn shade and Cameroon, and Sumatran Sumatra come to mind. Leaf of those types is too thin to be able to withstand the longer fermentation needed to darken it. Nearly all sun grown cigar tobacco has top leaves that can be made maduro.
"Maduro" has always been descriptive of dark tobacco of any type. There are now subdivisions of maduro like oscuro, medio tiempo, colorado, and others, but I consider these sub groups to be mostly marketing words, descriptions of different shades of dark.
The more intense the sun exposure, the darker and thicker the leaf.
I'd be willing to wager that over half of wrappers called "maduro" by cigar makers today are in fact the Conn Broadleaf plant, whether grown in CT,PA or Central America. This is what is keeping cigar tobacco growing alive as a commercial venture in the Connecticut Valley these days, not the thousand acres or less of shadegrown raised there each year now.
CT