406 THE ZOOLOGIST. 
also a distinct effect upon the structure of plants. Thus in the 
Mediterranean regions Ranunculus jficaria, as compared with the 
typical species growing in England, “bears finer and larger 
flowers and leaves, so that it is generally recognised as the variety 
Calthefola.” Caltha palustris “ has itself no recorded variety in 
low-lying situations.” ‘‘ When, however, this plant manages to 
get away from its habitual environment, and to reach ‘ mountain- 
ous places’ (Hooker), it puts on characters which descriptive 
botanists have independently noticed and variously named as 
varietal or specific. It is commonly known as Caltha minor.” 
“Many experiments have shown that if plants, or their seeds, be 
taken from lowlands and planted on alpine regions, all those that 
change their structures at once begin to assume more or less the 
same anatomical and morphological characters as the plants 
normally growing in highland regions.”* Again, according to 
Kerner, a plant of the grass Glyceria fluitans ‘‘ growing on damp 
soil on the edge of a stream over the water had linear bluntly- 
powmted leaves, whose sheaths were on the average 15 cm. long, 
the blades 23 cm. long and 8°5 mm. broad. After this plant had 
been submerged under rapidly-flowing water in the following 
year, leaves unfolded, which tapered gradually to a point, with a 
sheath having a mean length of 47 cm., and blades 73 cm. long, 
but only 5 mm. broad. The blades produced in running water 
were three times as long, and actually rather narrower than in 
the air.” + According to Varigny, ‘‘ Curtiss had seen in some 
places near the Potomac Bidens cernua acquire a height which is 
six times the common average height of this plant, and he has 
seen the same in Oxalis stricta; C. Lemaire states in D’Orbigny’s 
‘Dictionary’ that, while cultivated hemp grows no higher than a 
metre and a half in France, in Piedmont it attains three and four 
metres; and if Italian stock is planted in France it rapidly 
reverts to the small variety in the course of two or three years.” 
“Tt is also well known that where mountain plants are transferred 
to the valleys and plains they lose the hairy covering which they 
generally possess, while valley plants transferred to the mountains 
acquire this same covering.” ‘ The common Dandelion (Taraza-. 
cum dens leonis) has in dry soil leaves which are much more 
** Henslow, ‘ Natural Science,’ vol. vi. pp. 886, 388, 389. 
+ Kerner and Oliver, ‘ Nat. Hist. Plants,’ vol. ii. p. 502, 
” > _aigities. 
