174 The American Naturalist. [February, 
If we wish however to distribute the number of plants according to 
the principal groups and on the basis of the most recent monographic 
works, we arrive at the following result: 
NO. SPEC. 
Dicotyledons 78,200 See Durand Index Gen. Phan. 1888. 
Gymnosperms 2,600 where the numbers are taken from 
Monocotyledons 19,600 | Bentham. and Hooker Gen. Plant. 
1862-1883. i 
Ferus 2,685 See Hook. and Bak. Syn. Filic. 
1868-74. 
Equis. Marsil. Lycopod. 565 See Baker Fern Allies 1887. 
osses 2,303 See Mueller Syn. Muse. 1849-51. 
Liverworts 1,641 See Gott. Lind. Nees, Syn. Hep. 
1844. 
Lichens 5,600 See Krempelhuber Gesch. Lich. 
1870. ; 
Fungi 11,890 See Strienz Nom. Fung. 1862. 
Algae 6,200 See Kutzing Spec. Alg. 1849. 
Total 131,104 
But this number (131,104) is greatly increased by recent and vigor- 
ous contributions made especially in the vast field of the Cryptogamis 
in consequence of the improvements made in the microscope and the 
increased number of observers. In fact, according to Underwood, the 
American hepaticologist (efr. Bot. Gaz. 1892) from 1844 to the present 
time the number of. Liverworts by researches made in more regions 
the world has doubled. And as for the Algae according to my K E 
colleague, G. B. De Toni, upon documents collected by him and in part 
published in his admirable Sylloge Algarum, the number of species 
described up to to-day is distributed as follows : 
NO. SPEC. 
Chlorophyceae 2,798 (Syll. Algar. Vol. I, 1889.) 
Cyanophyceae 
Phaeophyceae 1,100 * 
Florideae 2,100 “ 
Bacillariaceae (Diat.) 5,000 (Syll. Algar. Vol. II et seq.) 
Characeae 200 
Total 12,178 
