What are the growths on my tomato plant?

So, I have three tomato plants in pots. They started out strong, with smooth, green stems. But after being stressed by storms and heat they began to grow greenish-brown “beards” up the stems. These are dense in some regions and not in others. They are firm to the touch but can be broken off. They are more dense towards the base and seem to sometimes accompany new shoots. What are these growths? I can provide a picture if necessary.