220 DR. A. C. SEWARD: 
My object to-day is to give a few examples of the application of palæo- 
botanical enquiry to problems of plant geography ; to endeavour to follow 
for a short distance into the ages which man never knew the history of some 
families of Ferns ; to trace their wanderings and if possible to discover their 
original homes. The alluring task of interpreting and reconstructing the 
relics of ancient floras hag its dangers and limitations: our efforts to make 
them live may produce a state of mind like that of a College Biographer who 
describes how in a nightmare he heard from an assembly of past generations 
of men whose lives and deeds he had attempted to portray, a hum of deep 
dissatisfaction directed against some one who they declared had scandalously 
misdescribed their careers in life. 
No apology is needed from anyone honoured by-an invitation to deliver 
the Hooker Lecture who chooses as his subject a problem connected with 
geographical distribution ; it is the quality of the matter and not the theme 
which causes misgiving. The study of plant geography if confined to the 
present must obviously be incomplete ; the data gathered from existing plants 
must be supplemented by records of the rocks—records, as Darwin said, 
which represent a short chapter of the last volume of a history imperfectly 
kept, and of this chapter only here and there a few lines. Though in all 
palæobotanical work the student is necessarily at a disadvantage because of 
the poverty of the documents, there are certain groups and families which 
promise some measure of success. The remarkable series of papers by Prof. 
Bower on several recent Ferns, which forms a worthy continuation and 
extension of the work of the Hookers, has stimulated botanists to take a 
wider interest in the inter-relations and past history of the several families, 
Once established, Ferns have a considerable power of spreading by vege- 
tative means ; the lightness and resistant nature of the spores enable them 
to play a successful rôle as colonisers and as emigrants to new countries. 
When Treub visited the remnant of the devastated Island of Krakatau three 
years after the series of violent eruptions he found eleven species of Ferns 
among the pioneers of the new flora. As a class Ferns are cosmopolitan, 
though certain families, genera, and species are strictly limited in range and 
highly sensitive to the influence of physical or climatic conditions. The 
familiar Bracken Fern iliustrates in a wonderful degree capacity for adap- 
tation to different climates and success as a traveller; but in what part of 
the world its journey began we cannot tell. Far within the Arctic circle 
Cystopteris fragilis lives through the Greenland winter : it grows in Morocco, 
Abyssinia, and South Africa and extends along the Andes through several 
degrees of latitude. Polystichum Lonchitis is at home at an altitude of 2000 
metres in the Swiss Alps; it flourishes in Northern Greenland, North 
America, Northern India, and in China. Another species, Polystichum 
capense, occurs in the Island of New Amsterdam in lat. 37° 5/ S., where it is 
said to grow almost as high as a man, and on the high plateau of Juan 
