FERNS. 



47 



tree-ferns, bear their graceful crowns on slender stems 

 twenty to thirty, or even fifty feet high. It is this 

 immense variety rather than any special features that 

 characterises the fern-vegetation of the tropics. We have 

 here almost every conceivable modification of size, form of 

 fronds, position of spores, and habit of growth, in plants 

 that still remain unmistakably ferns. Many climb over 

 shrubs and bushes in a most elegant manner ; others 

 cling closely to the bark of trees like ivy. The great 

 birds'-nest fern {Platy cerium) attaches its shell-like 

 fronds high up on the trunks of lofty trees. Many 

 small terrestrial species have digitate, or ovate, or ivy- 

 sliaped, or even whorled fronds, resembling at first sight 

 those of some herbaceous flowering-plants. Their 

 numbers may be judged from the fact that in the 

 vicinity of Tarrapoto, in Peru, Dr. Spruce gathered 

 250 species of ferns, while the single volcanic mountains 

 of Pangerango in Java (10,000 feet high) is said to 

 have produced 300 species. 



Ginger-ivorts and wild Bananas, — These plants, form- 

 ing the families Zingiberacese and Musacese of botanists, 

 are very conspicuous ornaments of the equatorial forests, 

 on account of their large size, fine foliage, and handsome 

 flowers. The bananas and plantains are well known as 

 among the most luxuriant and beautiful productions of 

 the tropics. Many species occur wild in the forests ; 

 all have majestic foliage and handsome flowers, w^hile 

 some produce edible fruit. Of the ginger- worts (Zingi- 

 beracese and Marantaceae), the well known cannas of our 

 tropical gardens may be taken as representatives, but the 

 equatorial species are very numerous and varied, often 

 forming dense thickets in damp places, and adorning the 



