Yeap, it may caused by dozens of weird reasons, but frankly its doesn't fancy meSince the oldest leaves are the same as of the neighboring crypts, this is obviously not a stable clone. While the specimen with the light veins doesn't appear to be of especially poor health, I suspect this color effect is caused by some nutrient problem (could be due to a virus infection or a dozen other causes...).
I'm almost tempted to guess at elliptica but the 2 pics just don't show enough details to make any educated guess. Any flowering crypts in this population?
Plant collected on beginning of this year (same pattern), all leaves are newly grown, and so do the neighbour plants. I don't even remember he told me he found this plant months ago until he show me the photos. Nothing fancy, but lets have some fun guessing...I spotted a Cryptocoryne spotting similar "light vein" patterns among a healthy bunch of C. pontederiifolia during one field trip a few months ago.
This is a close up view of that single plant in my emersed tank.
For a few months, every new leaves that emerged had the "light vein" patterns until recently, I found that the newer leaves no longer have such patterns and the older leaves markings are getting less and less apparant. I have try to post a updated photograph of that plant now tonight when I reach home.
Conclusion for my case: likely a nutrient problem.