VI 



an intermediate group. They have creeping or erect stems ; 

 their leaves are small/sessile, whorled, or imbricated, and their 

 fructification, which is spiked or axillary, consists of bivalved 

 cases, containing minute powdery spores. Of this order, 

 but few representatives are known to inhabit South Africa. 



§ 12. In most true Ferns, but especially in the dorsiferous 

 ones, the peculiar course, position, distribution, and rami- 

 fication of the nerves and veins, placed at the back of their 

 fronds, are highly important for the supply of superior generic 

 characters, being, as they are, closely connected with the 

 insertion of the organs of fructification. They, therefore, 

 are very valuable also in the arrangement of fossile Ferns, 

 which, as we learn from geology, abounded in great number 

 and variety during the carboniferous epoch of the earth, and 

 of which some hundred species, belonging to different genera, 

 have been described. 



§ 13. Although Ferns exist in nearly all parts of the globe, 

 yet countries situated within or somewhat beyond the tropics, 

 eeem to be most genial to their growth and development. 

 They generally delight in warm, moist, shady localities, and 

 thrive best in woody, mountainous regions. In the western 

 districts of the colony of the Cape of Good Hope they are 

 proportionally rare for that reason, but increase in species 

 towards the east, and become frequent and distinct in the 

 dense woods, mountain ravines, and near the cascades of 

 Natal. The aboriginal forests of British Kaffraria, as yet 

 unexplored, undoubtedly conceal strange forms, quite new to 

 the scientific world. 



§ 14. If we estimate (by moderate calculation) the entire 

 number of South African plants at about 12,000 species, out 

 of which one thousand, at least, are cryptogamic or cellular, 

 it then becomes apparent, that the Ferns are but poorly 

 represented in this great and imposing assemblage, forming 

 hardly one-sixtieth part of the whole Flora, and scarcely one- 

 fifth part of the plants of the lower classes, known to exist 

 in so wide and rich a tract of territory. 



