ON EEPEODTJCTION. 375 



their appearance at Kew, tlie only specimen in tliis country 

 then known being in the herbarium of the British Museum, 

 which I had not then seen. The botanical collector, Allan 

 Cunningham, failed to find it in Tasmania, and was very 

 much surprised on my presenting him with fine specimens 

 grown at Kew. This was also the case with Doodia 

 blechnoides, and Aspleiiium squamulata, by what means the 

 spores of these plants found their way into the pots at the 

 hothouses at Kew it is impossible to say. 



In spite of the very delicate nature of the prothallia, 

 it is nevertheless endowed with great vitality, as may 

 be seen by Ferns appearing on dry rocks, walls, and 

 such like, resisting the extremes of heat and cold. For 

 example, in 1829, I found a plant of Geterach officinarum 

 growing in a crevice of masonry on one of the towers of 

 the new palace at Kew (since taken down). As this Fern 

 is not found wild near London, it would be useless to 

 speculate where the solitary sj)ore came from ; it seemed, 

 however, to have found a proper nidus in the crevice, 

 enabling it to germinate and resist all untoward influences, 

 ta pass through the prothallium state, and become a plant. 



I must here state, that not long after Count Suminski's 

 discovery became known to me my sight began to fail, 

 which necessitated me to give up the use of the microscope, 

 therefore my own practical observations on this important 

 subject are but limited. 



In many cases Ferns not only reproduce their like by 

 spores, but also by the viviporous buds generally produced 

 on the upper side of the frond, or on the apex of the fronds 

 or segments, which when mature become plants. This is 

 specially characteristic of many species of Asplenium, 

 Ooniopteris, Woodtvardia, Meniscium, and others ; but so 

 far as has come under my notice, no bulbils are produced 



