368 FERNS. 



the surface of this a number of buds grow out which 

 are prolonged into young plants, and then the knob 

 and wire decay. 



Many persons must have admired the noble speci- 

 mens of Platycerium alcicorne, which for several years 

 has grown suspended against the wall of the tropical 

 fernery in Kew Gardens. But perhaps few have 

 penetrated the mystery of those great succulent semi- 

 globular leaves, like those of a large cabbage-heart, 

 which adhere by their edges to the suspended board. 

 The first frond formed is upright and spoon-shaped ; 

 then one comes, which is thick and circular, project- 

 ing horizontally, and presently curving downward : 

 after this, erect fronds again grow, which develop 

 flat forking tips, like the horns of an elk ; and then a 

 pair of the globose recurved form, one on each side, 

 covering up the base and the roots in their ample 

 hollow. Why this peculiarity of growth ? The Fern 

 is a native of tropical Australia, where it grows on the 

 perpendicular trunks of great forest trees, and must 

 often be exposed to droughts. These thick recurved 

 fronds afford a protection to the root and heart of the 

 plant, enclosing those parts in a tight box, from which 

 evaporation with difficulty proceeds. Other species 

 of the genus, whose fronds spread over the ground, 

 protecting the base of the plant and the surrounding 

 soil with their shadow, are not exposed to the same 

 peril, and are entirely devoid of this peculiar manner 

 of growth. 



The microscopist may find many highly interesting 



