Bee HETEROMORPHY. 
the leaves. In ferns it is likewise of frequent occur- 
rence, markedly so in Scolopendrium D Urvillei, in 
which plant every gradation from a simple oblong 
frond to an exceedingly divided one may be found 
springing from the same rhizome at the same time. 
A similar protean state, but little less remarkable, 
occurs in many of our British ferns, notably m Scolo- 
pendriwin vulgare, of which Mr. Moore enumerates no 
fewer than 155 varieties, many of the forms occurring 
on the same plant at the same time. Cultivators have 
availed themselves of this tendency to produce multi- 
form foliage, not only for the purposes of decoration 
or curiosity, as in the many cut-leaved or crisped-leaved 
varieties, but also for more material uses, as, for in- 
stance, the many varieties of cabbages, of lettuces, 
&e. Most of these variations are mentioned under 
the head of the particular morphological change of 
which they are illustrations. 
The effect of a change in the conditions of growth 
in producing diversity in the form of the leaf may 
be here alluded to. Ficus stipulata, a plant used to 
cover the walls of plant-stoves in this country, and 
growing naturally on walls in India, like ivy, produces 
leaves of very different form, size, and texture, when 
grown as a standard, from what it does when adhering 
to a wall. Marcgraavia wmbellata furnishes another 
example of a similar nature, as indeed, to a less extent, 
does the common 1 
Allusion has been already made to the occasional 
persistence of forms in adult life, which are commonly 
confined to a young state, as in the case of some 
conifers which present on the s same plant, at the same 
time, two different forms of leaves. Mention has also 
been made of the presence of adventitious buds on 
leaves and in other situations. The leaves that spring 
from these buds are usually of the same form as the 
other leaves of the plant, but now and then they differ. 
Of this a remarkable illustration is afforded by a fern, 
1 «Nature-printed Ferns,’ 8vo edition, vol. ii, p. 197. 
