158 FOOTNOTES FROM 



have contended that the spore germs of the lower cryp- 

 togamic plants are in all cases precisely the same, deve- 

 loping themselves into different plants according to the 

 medium and the circumstances in which they are placed : 

 becoming palmellas when produced on moist rocks, con- 

 fervse in streams, confervoid mosses on shady banks 

 and fields, lichens on dry rocks when stimulated by the 

 action of light, and fungi when produced on decaying 

 substances, and excluded from air and light ; and this 

 opinion seems to be strengthened by the fact so well 

 known to botanists, that the permanent organization of 

 the lowest plants is very frequently only the temporary 

 or transitional condition of higher, and that so close is 

 the resemblance between them that without due care in 

 watching the progress of their development, they may 

 easily be set down as distinct species. To this theory 

 of development, however, plausible though it looks, I 

 do not subscribe. Some of these productions may not 

 be autonomous, some may seem to pass into each other 

 by intermediate forms, and may bear a close resemblance 

 to the primordial stages of plants belonging to other 

 tribes ; but still there are real species among these 

 lower genera species which are permanent and do not 

 undergo any further transformation, for in the circum- 

 stances in which they are found they can exist and mul- 

 tiply and perfect their fructification independently. Few 

 objects are more beautiful and interesting under the 

 microscope than some of these obscure bodies, and their 

 study is absolutely necessary to the physiologist, if he 

 wishes to obtain a clear insight into the real character 

 and phenomena of growth and reproduction in the higher 



