THE FERN BULLETIN 



87 



also because of its ubiquity it is found more commonly 

 than any other about dwellings and plantations, its 

 huge lace-like fronds lending an unusual decorative 

 charm to scenes already novel and interesting to north- 

 ern eyes. The formation of groves of this species 

 in relatively dryish open situations is almost unique 

 for the family although a few, (e. g. Alsophila ar- 

 mata) are more or less gregarious in partial shade and 

 many others of our American species are found in 

 colonies in the deep wet forests. In New Zealand the 

 social tendency has even resulted in the formation of 

 large groves under intensely humid conditions. One 

 of these which Colenso came upon in the forest called 

 "Seventy-mile bush" in North Island is described by 

 him as follows : 



"On a flat in the heart of the forest, in a deep hollow 

 lying between steep hills, the bottom which for want 

 of drainage was very w r et and uneven and contained 

 much vegetable mud and water even in the driest sum- 

 mer season I found a large and continuous grove or 

 thicket of very tall tree ferns, chiefly Dicksonia squar- 

 rosa and D. fibrosa with a few Cyathea dealbata inter- 

 mixed, with but few forest trees and shrubs growing 

 scattered among them. I suppose they occupied three 

 rods of ground and I estimated their number to be 800 

 or 1,000. They were all lofty, from 25 to 35 feet high 

 and in many places growing so close together that it 

 was impossible to force one's way through them/' 



The stem or trunk of the Cyatheaceae varies greatly 

 in dimensions, shape, and direction, and in most char- 

 acters of outward appearance and covering though for 

 a given species these features are, with a few excep- 

 tions fairly constant in mature individuals. The tall- 



