Tomato Genetics at work.
It doesn't take long to pick them out, can you see them. 'Blind' or 'Mule' plants appear in some varieties of tomatoes. The two photos attached show what's commonly referred to as a tomato plant having a blind leader at their early stage in life. If planted and let grow, they won't form a growing tip, because it just never formed.
Mule isn't a common term that gets used much, but it does exist. It's often used because it will never reproduce 'offspring'. Sometimes, a plant will be classed as blind/mule when in fact it does grow a normal growing tip, but then it 'grows out' while the plant is still young. When I did my training in Horticulture, the teachers had never heard of this and thought I was pulling their leg, but after working with tomatoes for a time, it will in fact show up.
