[6] Wallroth 1825.

[7] Agardh 1820.

[8] [See p. 27.]

[9] Schwendener 1867.

[10] Fink 1913.

[11] Lindsay 1876.

[12] Nylander 1869.

[13] Crombie 1891.

[14] Nylander 1891.

[15] Crombie 1874.