Confluent node-rewriting hypergraph grammars represent the most comprehensive known
method for defining sets of hypergraphs in a recursive way. For a large natural subclass of
these grammars, we show that the maximal rank of hyperedges indispensable for generating
some set of hypergraphs equals the maximal rank of the hyperedges occurring in the
hypergraphs of that set. Moreover, if such a grammar generates a set of graphs, one can
construct from that grammar a C-edNCE graph grammar generating the same set of graphs.