332 IIETEROMORPHY. 



the leaves. In ferns it is likewise of frequent occur- 

 rence, markedly so in Scolopendr'mm D^UrviUei, 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 in Scolo- 

 2)endrinm 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 fohage, 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, 

 &c. 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. Marcgr'aauia umhellata furnishes another 

 example of a similar nature, as indeed, to a less extent, 

 does the common ivy. 



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 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, 

 ' ' Nature-printed Ferns,' 8vo edition, vol. ii, p. 197. 



