176 



PRINCIPLES OP PLANT-TERATOLOGY. 



abnormally, they may become permanent, as in a ' 

 specimen of a stone-pine (Pinus Pined) observed by 

 Grtibler, in which throughout the plant primordial 

 foliage only was developed. Also shoots bearing these 

 primordial leaves only may be induced to reappear as 

 a result of artificial mutilation, as, e.g., by cutting 

 back mature needle-forming shoots of the stone-pine ; 

 and these juvenile shoots in this case represent pro- 

 liferations of the short-shoots (PI. VII, fig. 2). In 

 several genera of the Cupressinege (Juniperus), cypress 

 (Cupressus), Gallitris, Ghamsecyparis, and arbor-vitse 

 (Thuja) the contrast between the juvenile and mature 

 foliage is marked. The former consists of spreading 

 needles (PI. XVI, fig. 3), the latter of needles which are 

 almost wholly concrescent by their upper surface with 

 the shoot (PI. XVI, fig. 2). In the common juniper 

 (Juniperus communis) the juvenile form constitutes 

 the only type of foliage of the mature plant. In male 

 plants of J. cliinensis many twigs bearing the juvenile 

 foliage constantly appear among those bearing the 

 mature type, so that it is practically a normal feature 

 representing an inherent tendency towards reversion. 

 Quite large plants may be grown from cuttings taken 

 either from the juvenile shoots on the mature plant 

 or on the young plant ; such forms, whether their 

 origin be from Juniperus, Cupressus, or any of the 

 other genera, have been assigned by horticulturists 

 the name of Betinospora, e.g. B. squarrosa and B. 

 plumosa, so well-known as handsome garden shrubs, 

 represent merely the juvenile stage of Cupressus pisi- 

 fera ; the shrubs known as B. dubia and B. ericoides, 

 etc., are but youthful forms of Biota orientalis and 

 Thuja occidental) 's. Gryptomeria "elegans" is the 

 fixed juvenile condition of G. japonica. Griard ob- 

 served a twenty-year old Biota whose leaves had all 

 been devoured by insects ; as soon as new shoots were 

 formed they were all cylindric instead of flattened, and 

 bore, instead of squamiform leaves, the acicular ones 

 of Betinospora dubia. 



