58 
dicotyledonous plants, one the nodus integer, from all parts 
of which the fibrovascular tissue proceeds into the leaf; 
the other the nodus partialis, where the fibrovascular tissue 
passes into the leaf at one point only. The nodus integer 
is universal in the order, and Dr. Grisebach considers that 
by this character Gentianacee are certainly known from 
Cinchonacee, Spigeliacez, and others. 
The organization of the flower of Swertia perennis and 
Gentiana lutea, is traced from the earliest period when it is 
distinctly visible up to the state of maturity. He finds the 
petals originally distinct, although eventually consolidated 
into a monopetalous corolla; the stamens distinct from the 
corolla, and exactly like nascent leaves, although eventually 
adherent to the petals; and the carpels also distinct; the con- 
solidation of all these parts takes place subsequently, and 
when the flower bud is about a line long. The placentation 
of Gentiana lutea is from the beginning marginal to a car- 
pel, and consequently at variance with the modern views of 
Schleiden and Schykofsky, who deny the truth of the theory 
that the origin of ovules is from the margin of carpellary 
leaves, and refer all placentation to the growing point. 
The author next considers the limits, principles of division, 
and affinities of the order; he admits the small natural order 
Columelliacez, and proposes a new order (Bolivariacee ) to 
include Bolivaria and Menodora. The geographical dis- 
tribution of the order is considered at length, and at the same 
time several general questions of interest in Botanical 
geography are discussed at considerable length. It is found 
that in all 343 Gentianaceous plants are known, and that the 
only parts of the world in which some one or other does not 
occur, are some islands in the Pacific, the tropical parts of 
New Holland, Timor, Sumatra, and some other parts of the 
Polynesian Flora, the deserts of Africa, the littoral of Vene- 
zuela ; and that they have scarcely been found on the moun- 
tains of Southern Europe. Of the species, 210 are tropical 
and 133 are extratropical. 
The order is divided into 40 genera, distributed through 
seven tribes; the detailed account of which is preceded by an 
excellent analytical table of the genera, tribes and species. 
Of Exacum 13 species are enumerated, of the beautiful genus 
Sabbatia 11, of Erythrea 17, of Lisianthus 33, and of Gen- 
tiana, to which are reduced most of the genera separated by 
d 
aal. 
