FROM THE STANDPOINT OF AN IDEALIST. 451 
hemispheres are about 56 per cent. for the tribes, less than 20 per cent. 
for the genera, and about 1 per cent. for the species.: As indicated in the 
table of results (Table T.), this subject has only been sampled for the tribes, 
genera, and species; but reference should there be made to the accompanying 
explanatory remarks. Yet the consistency in the results leaves no doubt 
that the general behaviour of the tribe, the genus, and the species is correctly 
illustrated in the above percentages. Here we perceive that the connection 
between the Old and the New Worlds is greatest with the family, less with 
the tribe, smaller still with the genus, and least with the species. Such a 
result is in perfect accord with what we should expect from the successive 
differentiations of a world-ranging family-type into tribe, genus, and species, 
the range contracting as one goes down the scale. The effect of the opposite 
method of regarding the species as diverging into the genus, the genus into 
the tribe, and the tribe into the family would be chaos. 
But although 70 per cent. of the families occur in both worlds they 
represent in very different degrees the community in families between the 
east and the west. For instance, the original distribution of the generalized 
family-type in both worlds would be best exemplified now by a family of 
which all the tribes belong to both hemispheres. At the other extreme the 
connection implied by the community in families between the Old and 
the New World would be near its breaking-point in a family where no 
tribes were the common property of both hemispheres, and where most of 
the tribes were gathered together in one of them. The possibility thus 
presents itself of constructing a scale representing the various stages of 
detachment from a both-world distribution. Taking an imaginary family 
holding thirteen tribes the writer has framed such a scale, the first grade 
claiming the families where all, or nearly all, the tribes are common to both 
worlds, the complete detachment being illustrated in the eighth or last 
grade, where all the tribes are restricted to one and the same hemisphere. 
Such a grading of families would raise many difficulties, some of which 
ought not to prove insurmountable for the differentiation hypothesis. It is 
not possible, however, to do much more than draw attention to this method 
here. It will be sufficient to mention that the Composite, the Aracez, and 
the Betulaces representing, respectively, the cosmopolitan, the tropical, 
and the temperate families, would find their place in the first grade. But 
the anomalies of this sort that are displayed in framing such a scale are in 
themselves instructive; and it is to be doubted whether a much more 
effective plan could be devised to illustrate the unequal value of families 
and to emphasize the necessity of grouping all families under a few great 
alliances. For instance, the Scitaminez are represented in this scale by 
four families, the Marantacew, the Zingiberacese, the Musacew, and the 
Cannaces, which are scattered up and down its grades. From the stand- 
EINN, JOURN.—BOTANY, VOL. XLIV, 2P 
