.l-,8 



STEM-STRUCTURE 



common ancestral type, is as plainly decipherable as in the 

 Conifers. 



The appearance of the stem in transverse section is very 

 similar to that of a Dicotyledon having secondary growth. The 

 Scotch Fir affords a typical example (Fig. 196, A). Here the 



Fig. 195. — Seedlings of various Conifers. A, Scotch Fir (P(»»s sj'/rcsAr;s). 



B, Cypress {Cupressus), showing tlic two cotyledons and plumule. 



C, Larch (Larix), older seedling which has already produced several 

 dwarf-shoots. Cot., cot3'ledons ; d.s., dwarf-shoot ; /;., hjrpocotyl. 



irregular outlme is due to the adherent bases of the scale-leaves 

 which are occupied by a large-celled tissue (Fig. 196, B), on 

 whose inner side the cork-cambium {Ca.) arises. With the pro- 

 duction of cork, therefore, the epidermis [e.) and the dwarf-shoots 

 become exfoliated, so that the older branches have a relatively 

 smooth surface. The narrow cortex is rather lacunar and con- 



