f 
204 ALTERATION OF POSITION. 
on the direction of branches, thus Dr. Falconer, as 
quoted by Darwin,’ relates that in the hotter parts of 
India ‘‘ the English Ribston-pippin apple, a Himalayan 
oak, a Prunus and a Pyrus all assume a fastigiate or 
pyramidal habit, and this fact is the more interesting 
as a Chinese tropical species of Pyrus naturally has this 
habit of growth. Nevertheless many of the fastigiate 
varieties seen in gardens have originated in this country 
by variation of seeds or buds. 
M. Carriere has also recorded a curious circumstance 
with reference to the fastigiate variety of the false 
acacia Lobinia pseudacacia ; he states that if a cutting 
or a graft be taken from the upper portion of the tree, 
the fastigiate habit will be reproduced, and the branches 
will be furrowed and covered with short prickles ; but if 
the plant be multiphed by detaching portions of the root- 
stock, then instead of getting a pyramidal tree with erect 
branches, a spreading bushy shrub is produced, with 
more or less horizontal, cylindrical branches, destitute 
of prickles.” 
Eversion of the axis——In the case of the fig, the peculiar 
inflorescence is usually explained on the supposition 
that the termination of the axis becomes concave, 
during growth, bearing the true flowers in the hollow 
thus formed. The cavity in this case would probably 
be due not to any real process of excavation, but — 
to a disproportionate growth of the outer as contrasted — 
with the central parts of the fig. Some species of 
Sempervivum have a similar mode of growth, so that 
ultimately a kind of tube is formed, lined by the leaves, 
the central and innermost being the youngest. The 
hip of the Rose may be explained in a similar manner 
by the greater proportionate growth of the outer as 
contrasted with the central portions of the apex of the 
flower-stalk. In cases of median prolification, already 
referred to, the process is reversed, the central portions 
1 * Variation of Animals and Plants,’ ii, p. 277, 
* Quoted in ‘ Gard. Chron.,’ 1867, p. 654. 
