What do you mean by grapevine? Explain two types of grapevine systems.

Grapevine refers to the part of informal communication. Grapevine cuts across formal channels of communication. There is no orderly path of travelling of information.
Two types of grapevine systems are:
(a) Gossip chain. In this one person is likely to tell many.
(b) Clusters. In this one person tells to selected few and some of the receivers pass on the information to few others, while some keep it to themselves.
(c) Single strand
(d) Probability