William Joshua and fresh water algae

In 1894, the Banffshire Journal published a long article about William, mainly on research he had carried out on rotting turnips and a possible link to an insect. The article painted a wider picture of William’s researches including:

“Mr Sim has also done good work in botany; and some time ago he discovered three species of fresh water Algae new to Britain.”

In 1882, William Joshua, a naturalist from Cirencester, advertised in Hardwicke’s Science Gossip, a journal which the Sims read and to which they contributed short articles. He was seeking other naturalists to correspond with him and exchange specimens of algae. One year later, Joshua published an article about fresh water algae and many of those he listed had come from Den of Gight. This was a location with which the Sims would have been familiar – but which was unlikely to have been known to Joshua unless he had help. Did William find the new algae and send them to Joshua who published the find?

I have found some references to William Joshua but nothing, such as letters, that provide a definite link. Is there anything out there?