GENERAL REVIEW OF CONIFEROUS PLANTS. 49 



SCIENTIFIC CLASSIFICATION. 



The rank or position assigned to the Coniferse in the scientific 

 classification of the Vegetable Kingdom now universally adopted 

 and known as the Natural System, will be easily understood from 

 the description of the various organs, especially those of repro- 

 duction, given in the preceding pages. -It has been shown that 

 the flowers are of the simplest possible structure, and that the 

 fertilisation of the seed-bearing ovules takes place without the 

 intervention of a stigma, and that the seeds are borne naked on 

 the upper side of the woody scales of which the cone or fruit is 

 composed. This character is also common to the Cycads and to 

 two genera of plants called Gnetum and Ephedra, so that all the 

 plants producing their seed in this manner have been constituted 

 a Class or Subdivision under the name of Gymnosperma, i.e., naked 

 seeded plants. It is the absence of an ovary that mainly dis- 

 tinguishes the Gymnosperma from all other flowering plants, and 

 with this is necessarily connected the difference in the mode of 

 fertilization alluded to, and also a difference in the structure of 

 the pollen grains.* " In their reproductive organs, therefore, the 

 Gymnosperma exhibit a decidedly lower type of organisation than 

 the Angiosperma (flowering plants), and in many respects occupy 

 an intermediate position between these and Cryptogams (flower- 

 less plants)." With the former they agree in habit, in the 

 possession of sexes, and in their vascular tissues being complete; 

 and with the latter they also accord somewhat in habit, the 

 resemblance between the branchlets of some Conifers and Club- 

 mosses being so great that Dr. Lindley could find " no obvious 

 external character, except size, by which they can be distinguished." f 

 There is a further analogy between Conifers and Selaginellas in 

 the pollen of the former and the microspores of the latter. { In 

 the anatomical structure of the wood, Conifers have been shown 



* For the explanation of this difference, which would he too intricate to introduce 

 here, the reader is referred to works on Stiuctural and Physiological Botany. 



t Dr. Lindley's Vegetable Kingdom, p. 221. 



X Die Pollenkorner verrathen eine Verwandschaft mit den Mikrosporen der Selugmcllen. 

 Sach's Zehrbueh, p. 488. 



