rd 
The result we have arrived at does not, therefore, 
eonflict with the theory of the migration of the flora into 
Transcaspia at the beginning of the quaternary period (see 
above p. 259). The great number of endemics moreover 
confirms ENGLER’s assertion that dry areas (he also mentions 
“the Asiatic Steppes’) whence a great number of plant types 
are excluded give rise to endemic species’). 
Among the non-endemic species of Transcaspia we 
distinguish between those which have a northerly, those 
which have an easterly and those which have a southerly 
distribution (see above p. 260). 
Northerly distribution is seen in such species as are 
distributed from Transcaspia over western Siberia and South 
Russia. The limit is fixed at about 46° N. Lat. (see above 
p- 262). Of such plants there are 306 or 40 p. cent. of all 
the species of Transcaspia; in the plant-list they are the 
species with the letter R included in the distribution-index. 
This is no small number, but the importance of the figure 
is lessened when we remember; (1) that with the exception 
of 29 of the 306 (9 p. cent.), they are equally distributed 
towards the east and south; (2) that only 96 species (12 
p. cent. of the total number of species) are common to both 
Transcaspia and the government of Yekaterinoslaw, (these 
are indicated in the list by R*) "The first’ of the” above 
points emphasises that the species occurring towards the 
North are on the whole widely distributed. The 29 species 
referred to (those indicated in the list merely by R) do not 
even extend far northwards, only one of them (Erodium 
Hoefftianum) is found as far north as Yekaterinoslaw. Most 
of them occur on the Kirghiz steppe which as already stated 
is very similar to Transcaspia. Nor do many of the remain- 
ing plants with a northern distribution reach the true steppe 
or forest areas. 
As regards the second point (2), the number of species 
common to Transcaspia and Yekaterinoslaw, it may be 
remarked that, with the exception a few Chenopodiaceae and 
Lycium and Statice, the species common to both countries 
1) 1879 p. 10, 1882 p. 50. 
