This is strikingly illustrated, according to Alph.

de Candolle, in those large groups of terrestrial plants, which have very few aquatic members; for the latter seem immediately to acquire, as if in consequence, a wide range.

I think favourable means of dispersal explain this fact.

I have before mentioned that earth occasionally adheres in some quantity to the feet and beaks of birds.

Wading birds, which frequent the muddy edges of ponds, if suddenly flushed, would be the most likely to have muddy feet.