Well, violacea is a species; the question becomes what GENUS does it belong to? Have your seedlings ever bloomed? Are they vines (
Ipomoea violacea)? Are they orchids (
Phalaenopsis violacea)? Are they woodsorrels (
Oxalis violacea)? Fungus? Garlic? Gallic Roses?
Check out the Plant Identification Forum
HERE if you've got a picture - these guys are fantastic for plant ID.