[16] Crombie 1877.

[17] Crombie 1885.

[18] Fink 1913.

[19] Elfving 1913.

[20] Moreau 1918.

[21] Peirce 1898.

[22] French 1898.

[23] Morison 1699.

[24] Tournefort 1694 and 1700.

[25] Dillenius 1741.