116 ILLINOIS STATE ACADEMY OF SCIENCE 



opposite sides of a valley or on the lava flow of 1841 or 

 of 1881 as it stretches through both wet and dry regions. 



The flora of the island is highly endemic. Hillebrand 

 states that excluding the species introduced by man there 

 are 860 species, of which 653 or 76% are endemic with 40 

 endemic or peculiar genera, flgures which are approxi- 

 mately true in the light of present knowledge. Many 

 wonderful and interesting forms occur, e. g. the Silver 

 sword and Gunnera. 



It is, however, the fungi in which I am particularly in- 

 terested. Less than 130 species, aside from those of 

 economic crops, had been identified as occurring in the 

 Hawaiian Islands prior to my collections of the summer 

 of 1921, and very few of these had been recorded by pub- 

 lication. My own collections number something over 1200, 

 and represent trips into all types of floras. Examination 

 of some of these has been completed, and the results are 

 being published by the Bishop Museum; others are be- 

 ing studied. 



The genus Meliola and its near relatives are represeiit- 

 ed by 34 species on 58 hosts (4 on 4 hosts were previously 

 known). Porto Eico gave 103. The ratio to available 

 host species in Hawaii is .034 as against .046 in Porto 

 Rico, a very significant difference showing the Meliolas 

 to be approximately 50% more abundant in Porto Rico 

 than in Insular Hawaii. The Meliolas are strictly limited 

 to the ancient flora of the island and show decided evi- 

 dence of w^estem origin, being much more closely related 

 to the Polynesian flora than to that of South America. 

 This is particularly emphasized by the genus Meliolna, 

 typically PhiUipine. 



Transition genera between families are also of especial 

 interest. Thus the genera Meliola, Amazonia, Actinodo- 

 this present a series connecting the Microthyriacease 

 with the Dothideales, and I believe that there is evidence 

 from those studies that the present group of Dothideales 

 is of polyphyletic origin. An interesting case of evolu- 

 tion occurs on Perrottetia in that there are both a well 

 defined Amazonia and an Actinodothis on this host, 

 clearly related as is shown by the hyphopodia and spores 

 but now well differentiated into two genera ; an evolution 



