1 68 SCOTCH PINE. 



stage is much reduced, although still green and able 

 to maintain itself for a limited time, while the asexual 

 stage is the conspicuous part of the plant, in fact the 

 only part usually noticed, except by students and fern 

 propagators. 



From the fern to the pine is too great a step to be 

 well understood without considering some intermediate 

 type. Some species of Selaginella would answer this 

 purpose admirably, and it is to be regretted that no 

 species is sufficiently common in this country, either 

 wild or cultivated, to permit the introduction of direc- 

 tions for its study in this manual. It must therefore 

 suffice.to mention one feature of Selaginella indispens- 

 able for a clear understanding of the subject in hand. 



Selaginella, instead of having only one sort of spores, 

 as in the ferns and liverworts, has two, one small (micro- 

 spores), the other large (macrospores). When these 

 spores vegetate, the prothallium from the smaller one 

 bears the male organs (antheridia), and that from the 

 larger the female organs (archegonia). A very marked 

 feature is that the prothallia are greatly reduced, so 

 much so in fact that they never leave the spore or 

 become green, and the one from the smaller spore is 

 even reduced to a single small cell. 34 



To return to pine, we shall find that the reduction of 

 the sexual stage or prothallium is carried a step, and 

 quite a long step further than in Selaginella, while the 

 asexual stage is augmented in the same proportion. 

 The latter in fact is the pine tree the whole plant one 

 would naturally say. It must be borne in mind that in 



34 For further description see Bessey, Botany, p. 385 ; Sachs, Text- 

 book, p. 468. 



