234 



SCIENCE 



[N. S. Vol. XXXVIII. No. 972 



and '10), of Pierantoni (1909 and '10), who 

 succeeded in isolating and growing certain 

 forms in pure culture, tliat has furnished the 

 basis for a correct interpretation and for a 

 comprehensive study of these bodies in the 

 various groups of insects. 



Such a study has been com m enced by Dr. 

 Buchner and the extensive paper before us 

 considers primarily the intracellular symbionts 

 of the hemiptera. There is a very full his- 

 torical discussion which will be of great value 

 to other students of the general subject, and 

 which will serve to put the reader, be he bot- 

 anist or zoologist, en rapport with the topic. 

 Then follows a detailed discussion of the 

 author's own investigations. 



Of special interest are the data on the 

 method of infection of the developing eggs by 

 the organisms. This may take place in a dif- 

 fuse manner, as in the cockroaches, or it may 

 be very definitely localized, as in the aphids. 

 In any event, we are concerned with a heredi- 

 tary transmission of bacteria-like or yeast-like 

 organisms. 



Concerning the systematic position of the 

 forms studied there is little definite to be said, 

 though it is certain that the intracellular sym- 

 bionts of insects, as we know them at present, 

 do not represent a closely definable group. 

 The forms in the cockroaches are apparently 

 true bacteria and probably so also are those 

 of the ants. 



On the other hand, the multiplication by 

 budding, the type of mycelial formation, the 

 lack of structures comparable to spore of bac- 

 teria, the constant presence of a nucleus, and 

 oither characters in the other forms studied 

 are suggestive of the yeasts, and it is here that 

 most of the recent students of the subject are 

 inclined -to place them. Thirty-four species, 

 some of them new, loosely grouped here, are 

 described and figured. 



It is obvious from Buchner's studies that 

 these puzzling organisms are not to be re- 

 garded as parasites. So striking are some of 

 the specializations and adaptations which their 

 presence has brought about, that it is equally 

 impossible to regard them as mere commen- 

 sals. But certain as the author is that he is 



dealing with true symbionts, he is unable to 

 explain, satisfactorily, the advantage which 

 accrues to the host. 



Dr. Buchner's work is of fundamental im- 

 portance, but one must agree with him that it 

 is but a beginning. With the foundation work 

 done, the next few years should see wonderful 

 advance in our knowledge of this difficult 

 subject. 



Wm. a. Eilet 



Cornell UNivERSirT 



BOTANICAL NOTES 



SOME STATISTICS AS TO THE FLOWERING} PLANTS 



In this inquiry I have considered only the 

 proper Flowering Plants, Anthophyta ob 

 " Angiospermae," and have given most of the 

 numbers in thousands, for easier memorizing. 



Number of species of Flowering Plants dzl32,500 



Dicotyledons ±108,800 



Monocotyledons it 23,700 



In the Dicotyledons: 



Aiiflorae ± 54,000 



Calyciflorae ± 54,000 



In these again: 



Axiflorae — apopetalae ± 29,000 



Axiflorae — gamopetalae it 25,000 



Calyciflorae — apopetalae it 33,000 



Calyciflorae — -gamopetalae ± 21,000 



So there are: 



Of Apopetaloua Dicotyledons it 62,000 



Of Gamopetalous Dicotyledons it 46,000 



Again, there are in Dicotyledons: 



Oyaries, superior it 72,000 



Ovaries, inferior it 36,000 



Those with superior ovaries are dis- 

 tributed as follows: 



In Apopetalous species ± 50,000 



In Gamopetalous species ± 22,000 



Those with inferior ovaries are dis- 

 tributed as follows: 



In Apopetalous species it 14,000 



In Gamopetalous species it 22,000 



In the Monocotyledons: 



With ovaries superior it 12,000 



With OTaries inferior it 11,000 



In Monocotyledons gamopetaly has not 

 become established. 



So there are in the Flowering Plants: 



Of Apopetalous species it 86,000 



Of Gamopetalous species ± 46,000 



