318 : NOTICES OF BOOKS. 
graphy, as it is derived from a far greater amount of materials, and 
from the vegetation of a much larger area, than has ever before been 
submitted to such an amalysis. According to the generally-received 
(but probably enormously overrated) estimates of the number of known 
flowering plants in the whole globe, the proportion of Monocotyledones 
to Dicotyledones is as 1 is to 4'8, or nearly one to five. 
When we consider that the results derived from the ‘ Flora Rossica' 
are applicable to a temperate and Arctic Flora, and with hardly a trace 
of admixture of Tropical genera or families, this approximation of the 
proportional number of Exogenous and Endogenous plants to that of 
the whole globe, appears very remarkable, and opens a wide field of in- 
quiry, as we are led to ask whether the data are sufficiently accurate for 
such generalizations, or whether the diffusion of the two greatest classes 
of plants is really so equable throughout the globe as these facts would 
lead us to expect. Considering that the systematic compilation of the 
‘Flora Rossica’ was almost wholly due to the exertions of Professor 
Ledebour himself, and that he was particularly well versed in his sub- 
ject, the probabilities are great, that there is so much unity of purpose 
and design in the whole work, as that the proportions of the great 
groups may be deduced from its materials with much approach to ac- 
curacy. 
The most extensive Natural Orders described by Professor Ledebour 
` are the following :— 
Composite . . . . 909 Serophularnee . . . 222 
Leguminose . . . . 570 Rosacez, including Po- 
Orodferge . ..... pit 892 mez and Amygdalee. 220 
Grosses... Dal sy 24:869. 2 Oyperaeem: 5025. .::200 
Umbelifere . . . . 3832 Chenopodee . . . . 185 
Caryophyllee . . . 268 luilinepmii. ciora seco 
labis. o1. 10:xo219d 9827s oosOnehidem 2:21 200 06:09. 
Ranuneulacee . . . 228 
"There are besides many Orders, eontaining upwards of 80 species, 
which it is not necessary to enumerate here. The above will give 
some idea of the immense amount of materials with which Professor 
Ledebour had to deal; for whatever opinion may be entertained as to 
the validity of a great many of the species, the fact of upwards of 6000 
plants, whether species or varieties, having been subjected by a really 
careful and accurate botanist to a more or less critical examination, i$ 
