37 



in the greenhouse for checking the work of insects and fungi 

 and the methods of applying them, and a number of illustrations 

 of parasitic fungi were shown. 



Fred J. Seaver. 



TROPICAL FERNS' 



People who think of the matter at all often think of the ferns 

 as being a more conspicuous feature in the flora of the tropics 

 than in that of temperate regions, but whether this is really- 

 true or not depends very much upon local conditions. On 

 most of the Bahama Islands, where the soil is dry and rocky 

 and on the dry southern slopes of the larger West Indian islands, 

 such as Jamaica and Porto Rico, where the rainfall is light, as 

 compared with the amount of evaporation under the scorching 

 rays of the tropical sunshine, the ferns are usually rare and in- 

 conspicuous. In such places, as also in Bermuda, which is not 

 really tropical, the ferns are found chiefly in shaded sink-holes 

 and caverns, where moisture is more readily conserved. But 

 in the more humid parts of the tropics, as on the northern slopes 

 of the mountains of Jamaica and Porto Rico, where it rains 

 more or less on nearly every day in the year and where the annual 

 rainfall amounts to lOO or sometimes 200 inches, ferns are often 

 found in great luxuriance and abundance. The late Professor 

 Underwood of Columbia University, one of the most renowned 

 of the American students of ferns, has said that in walking a 

 distance of three miles on one of the paths in the rain forests 

 of the Blue Mountains of Jamaica one can gather as many as 

 one hundred diff^erent kinds of ferns without the trouble of step- 

 ping from the path. 



The Danish fern authority Christensen, in 1913, recognized 

 7,411 species of ferns in the world as a whole. Of these only a 

 few, perhaps 30, have been found in the Arctic Zone; only about 

 70 in all of Europe, and about 300, including the fern allies, 

 within the continental boundaries of the United States. It is 

 in the tropics and in the South Temperate Zone that the species 

 are most numerous. The stately and graceful tree ferns and the 



^ Abstract of a lecture given in the Central Display House of Conserva- 

 tory Range 2 on Saturday afternoon, December 22, 1923. 



