a JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



Millions of ' seeds '—in the physiological sense — were dis- 

 covered hanging on the trees and lying on the ground, but it was 

 as yet impossible to sow them and watch them grow ; the 

 beginnings of microscopic gardening were not yet. 



In the case of many introduced garden-plants inquiry into 

 their history and habits shows that each has passed through 

 some such phases as the following. 



It was discovered by a traveller seeking for plants, but not 

 concerned with, or not equipped for, any detailed botanical 

 examination of the species. 



Collected specimens were then sent home and carefully 

 figured, and found their rest in an herbarium, properly named 

 and classified. 



Seeds or other suitable portions of the living plants sooner or 

 later arrived, and were made the subject of experiments in garden 

 or greenhouse, and grown ; and as experience with such exotics 

 grew more and more, special methods of treatment were found 

 necessary, and varieties of cultivation soon followed. 



Now, the history of microscopic plants and of the methods of 

 microscopic gardening have been singularly like those of ordinary 

 plants and gardening. Prior to 1850 microscopic alga? and 

 fungi were being discovered by explorers in all directions, and 

 enormous stores of figured and suitably prepared and labelled 

 materials accumulated in collections. Then came one of the 

 most active periods botany has ever known. Unger had dis- 

 covered the spermatozoids of the moss in 1837, and Suminsky 

 had explained the fertilisation of ferns in 1848, while Hof- 

 meister's masterly treatise on the embryology of cryptogams 

 appeared in 1810 51, and the names of Thwaites, Williamson, 

 Carpenter, Berkeley, and other English workers are well known 

 in this connection ; but the microscopic alga? and fungi were 

 still a chaotic mass of collected forms, with the exception 

 of a few isolated observations. Thuret, in 1853, Pringsheim 

 and Oohn, In 1855, and De Bary about the same period were 

 initiating an epoch which may be said to be distinguished by the 

 observer watching the living plant and noting its peculiarities of 

 growth and development instead of merely collecting it and giving 

 it a name The publication of Berkeley's masterly treatise on 

 rryptogamic botany in 1857 marks the critical period. 



Spores of fungi especially were now sown and their germina- 



