VARIABILITY OF CONIFEROUS TREES. 187 



Cupressiis (including Retinispora and ChamcEcyparis), and 

 Thuya, have in many instances led to increased, confused, 

 and erroneous nomenclature. Fortunately, of late years, 

 many doubtful points have been satisfactorily cleared up, and 

 we are now enabled to correctly refer certain previously 

 acknowledged genera to their proper rank of species, and 

 species to that of variety. Notable examples of this kind 

 include Cryptoineria japonica elegans, in which only the 

 primordial leaves are produced ; the so-called Retinispora 

 ericoidcs and Biota meldensis, which are only undeveloped forms 

 of the Chinese arborvitae {Thuya orientalis), in which the scale- 

 like foliage is suppressed ; TJmya Ellw anger iana, a form of T. 

 occidentalis bearing both adult and juvenile foliage ; Rctijii- 

 spora leptoclada, R. squarrosa ; and some little-known forms 

 of Citpressus torulosa and Junipenis virginiana. 



Generally speaking, the origin of these forms may be 

 accounted for by the fact that amongst the cypresses, junipers, 

 and arborvitaes, the foliage of seedling plants is long and 

 needle-like, and in many instances, but at indefinite periods, 

 succeeded by scale-like leaves. At what period of their 

 growth this change of foliage may take place is very uncertain, 

 and that too, I have frequently noticed with different conifers 

 from the same batch of seedlings, some assuming the adult 

 foliage at an early date, while others remain in the primordial 

 condition for an almost indefinite period. Cryptomeria 

 japonica elcgans is an example of the latter kind, the prim- 

 ordial or juvenile character having been retained for thirty 

 years, at present no signs of breaking away from the seedling 

 stage being visible in a specimen of that age. Reti?iispora 

 ericoides (properly Thuya oriaitalis ericoidcs) is simply an 

 undeveloped form of the Chinese arborvitae, the fruit, as I 

 have seen, differing in no way from that of the species. 



By continual propagation from the juvenile stage a fixed 

 character may therefore be established, and many forms so 

 obtained are highly ornamental and of great value for orna- 

 mental purposes ; so that the practice amongst conifers is cer- 

 tainly to be recommended. Of Cupressus torulosa and Juni- 



