Born in tsarist Estonia to Baltic Germans, he was naturalised in Finland and had to negotiate the complex inter-war contests over that country's future.
It might also, perhaps, have been expected that naturalised plants would have belonged to a few groups more especially adapted to certain stations in their new homes.
To give a single instance: in the last edition of Dr. Asa Gray's " Manual of the Flora of the Northern United States, " 260 naturalised plants are enumerated, and these belong to 162 genera.
We do not know that even the most prolific area is fully stocked with specific forms: at the Cape of Good Hope and in Australia, which support such an astonishing number of species, many European plants have become naturalised.