They are very different. Seminole produces a small teardrop-shaped or elongated teardrop-shaped pumpkin (its shape is highly variable) that weighs 3-4 lbs. and matures roughly 85-95 days after the fruit sets. Dickinsen produces a very large fruit that can top out around 40 lbs. and matures in 100-115 days depending on weather conditions. Dickinsen has the shape of a tall, sort of oblong pumpkin, not the more rounded shape of a carving pumpkin. Both have a buff-colored rind. There also is a "larger fruited" strain of Seminole, seed generally available for it from Southern Exposure Seed Exchange or Baker Creek Heirloom Seeds, that produces a larger fruit than the original Seminole, but it still is a small fruit compared to Dickinsen.