CHAPTER VI 



CONIFERALES (PINACEAE) 



The Coniferales are the representative gymnosperms of the pres- 

 ent flora. They comprise 40 recognized genera, and approximately 

 350 species, constituting more than three-fourths of the present 

 gymnosperm flora. They are characteristic of the temperate regions 

 of both northern and southern hemispheres, presenting a sharp con- 

 trast to the Cycadales in their general geographical distribution. 



Before discussing the morphology of this great group, it will be 

 necessary to survey the material as it has been organized by taxono- 

 mists. Two families are recognized, the Pinaceae and the Taxaceae. 

 Among the Pinaceae distinct strobili are formed, whose overlapping 

 scales protect the ovules, and whose seeds ripen dry; while among 

 the Taxaceae distinct ovulate strobili (in the ordinary sense) often 

 are not formed, at least the ovules are frequently freely exposed, and 

 in any event the seeds develop a partially fleshy testa or an aril. Such 

 characters are superficial, but they are accompanied by important 

 morphological differences, so important in fact that the two families 

 must be presented separately. 



The Pinaceae include 29 of the genera and approximately 245 

 of the species, so that they are the dominant conifers. Four series 

 of forms are recognized, two of which are doubtless artificial assem- 

 blages, but they serve at present to catalogue the material, and may 

 be spoken of as tribes. 



The Ahietineae are spiral forms, and have almost completely 

 distinct bract and ovuliferous scale, winged pollen grains, and needle 

 leaves. They include 9 genera and approximately 129 species, as 

 follows: Pinus (75 species, throughout the northern hemisphere, 

 mostly in extra-tropical regions); Cedrus (3 species, in Asia and 

 northern Africa); Larix (8 species, in North America, Europe, and 

 Asia); Pseudolarix (i species, in eastern China); Picea (12 species, 

 in the extra-tropical regions of the northern hemisphere); Tsuga 

 (6 species, in North America, Mexico,' and Asia); Pscudotsuga 

 (2 species, sometimes merged with Tsuga, in North America); 



