ZOOLOGY AND BOTANY, MICROSCOPY. ETC. 375 



cherimoya to set fruit after several years of bloom led the author to in- 

 vestigate the matter. The construction and fragrance of the flowers of 

 all three species shows that they are entomophilous, and the author 

 finds that they are proterogynous. The petals are almost vertical until 

 the shedding of the pollen, leaving a small opening for the entrance of 

 insects. As the flowers develop a viscid fluid is secreted, covering the 

 syncarpium and apparently most abundant about twenty -four hours 

 before the the pollen is shed. As the time approaches for the discharge 

 of pollen, the petals spread outward and upward very rapidly ; at the 

 same time a strong fragrance is exhaled. The stigma can now be 

 approached by large insects, and, were the flower synchronus, self-pollina- 

 tion might be effected. A small beetle. Colastus truncatas, has been 

 found acting as pollinating agent in sugar apple and cherimoya flowers- 

 Another small insect found in flowers of sugar apple was identified as 

 probably belonging to the Pharaxonothi. A small thrips also frequents 

 the flowers of these Anonas. 



A series of pollination experiments was carried out on these three 

 species. Pollen was applied to the stigmas of twenty-seven cherimoya 

 flowers at the time of the discharge of the pollen in the flower ; all these 

 flowers dropped. Thirty-four flowers were pollinated twenty-four hours 

 or more before the shedding of the pollen, and all set. Experiments 

 with sugar apple and custard apple flowers gave similar results. 



The flowers of the pond apple, which belong to a different section of 

 this genus, have similar arrangements of andrcecium and gyncecium. 

 The flowers open to admit small insects about twenty-four hours before 

 the pollen is shed, exhaling a strong odour. Practically all the flowers 

 shed their pollen before sunrise, and are probably pollinated by nocturnal 

 insects, though the agent has not been detected. 



Since these investigations began, the cherimoya has. without artificial 

 pollination, set fruit sparingly in Florida, less than 20 ft. above sea level. 

 In Hawaii it fruits only at an elevation of many hundred feet. This 

 may be due to the presence there of certain insects not found at lower 

 altitudes. The sterility of cherimoya in Florida has doubtless been due 

 to the scarcity of blooms and to an insufficient number of insects to 

 assist in pollination. 



It has been proved that sugar apple hybridizes readily with cherimoya. 

 custard apple, and pond apple ; cherimoya has also been successfully 

 crossed with pond apple : hut so far. attempts to cross sour-sop, A. 

 muricata L., with these species, have failed. The extraordinary pro- 

 ductivity of a few individual trees suggests a change in regard to the 

 pollination of the flowers of these trees, possibly due to synacmy and 

 self-pollination. Should this lie confirmed, such trees would be of in- 

 estimable value in the creation of varieties independent of outside 

 agencies for fructification. 



Comes, 0. — Del Fagiuolo comvme (Phaseolus vulgaris L.) 



[An account of the history, properties, and cultivated races and forms of 

 the scarlet runner.] 



Atti R. Istit. Incoraggiamento Napoli, l'JO'J (1910) pp. 73-183. 



