







ANATOMY, AND LIFE-HISTORY OF THE CONIFERS. 



257 

















r n 











gra 





cone. Illustrations of these facts, as well as numerous transitional 

 stages, may be seen in various species of the genus Thuya, in Li- 

 bocedrus decurrens and L. macrolepis. These homomorphic 

 leaves may be compared with the primordial leaves produced out 

 of season, as will be more fully alluded to in the following para- 

 >h. They may also be compared with the similarly uniform 

 leaves of the species of Lycopodium. 



Primordial or Protomorphic Leaves. — In many cases the leaves 

 which immediately follow the cotyledons differ in form, attach- 

 ment, arrangement, and, to some extent, even in structure from 

 those which characterize the adult state of the trunk or branches. 



In Callitris, Frenela, Libocedrus, Thuya gigantea, Cupressus 

 glauca, C. sempervirens, C. nutkaensis, Lawsoni, funebris, macro- 

 carpa, Cryptomeria japonica, Sequoia gigantea, Phyllocladus, 

 Araucaria excelsa (see fig. 3, p. 234), some species of Abies, as in 

 A. Apollinis and grandis, in Pseudotsuga Douglasii, Picea excelsa, 

 Menziesii, orientalis, Larix Griffithii, Cedrus atlantica, the pri- 

 mordial leaves are in many rows, more or less linear, and entirely 

 free or but slightly concrescent at the base, but never appressed. 

 In the Piceas the pulvini are not observable at the base of the 

 lowermost leaves. 



The stomata are usually on the lower surface of these primor- 

 dial leaves, but sometimes on both, as in many species of Pintts*. 

 In Cedrus and Larix the primordial leaves are linear or awl- 

 shaped, mucronate, with longitudinal rows of stomata on all sides, 

 as in Picea. 



In Taxus baccata. Picea Menziesii. Tsuqa Mertensiana, Sequoia 









■ 



- 





■ 





















grea 



differ in appearance from the adult leaves. 

 In some species of Araucaria, as previously mentioned, the 



Daguillon 



presented 



x — « -«w*v*uo, iooy, p. luc, dan. It, puuiisiieu oin^o i»«*» jf-jf ~* • — r 



to the Society in November 1888, says the stomata are always to be found on 

 both sides of the primordial leaves, even in P. Strobus, where in the adult con- 

 dition they occur on the upper surface only. In Abies, in which genus the 

 adult leaves are in one plane, the same author describes the primordial leaves 

 as forming a whorl, whereas in Picea they are alternate, as are the adult leaves, 

 M also in CeJrm and Larix. where the adult leaves are tufted. The absence 









. . lerm 

 to 









t"re as compared with the permanent leaves are also alluded to by M. Daguillon. 



=*e also Beissner, « Ueber Jugendformen v. Pflanzen speciell von Coniferen," 



Berichte d. deutsch. Bot. Gesellsch. vi. 1888, pi 



XXX1H 









■ 























L 















■ 



■ 





■ 





