The red markings usually are only seen in very young suckers if at all, but they are not always present. The different shades of green are due to nutrition and sun exposure. Well fed bananas in the shade can be very dark green, while it is easy for them to become more yellow if they are lacking nutrients, especially when grown in full sun.
The red pseudostem with black markings (and that is was found in Wal-Mart) indicate a Cavendish of some sort, while the stockiness and short petioles indicate 'Super Dwarf Cavendish'.
Here is the 'Super Dwarf Cavendish' compared to 'Dwarf Cavendish' of roughly the same age and in the same conditions.
'Super Dwarf Cavendish' petioles. They are very short and compacted.
'Dwarf Cavendish' petioles. They are longer and noticeably different from the 'Super Dwarf Cavendish'.
