Febbuabt 12, 1909] 



SCIENCE 



267 



hybrids, although, attempts were persistently 

 repeated throughout the summer. However, a 

 few seeds were obtained from individuals hav- 

 ing respectively lata, gigaSj and intermediate 

 number of chromosomes and the plants de- 

 rived from these wiU form the chief subject of 

 study for the coming year. 



To summarize briefly: 



The first generation offspring of 0. lata 

 2X0- g^Qas ^ fall into three main groups 

 with respect to external characters and num- 

 ber of chromosomes; namely, lata, gigas-like 

 and intermediate. Considering external char- 

 acters only, the latter two should be further 

 divided and subdivided. 



Numbers of chromosomes are closely asso- 

 ciated with external characters in the first and 

 last, and probably also in the second group. 



Pollen grains of two parental forms differ 

 in number of lobes and these are inherited. 

 Anne M. Lutz 



Station fob Expebimental Evolution, 

 Cold Spbing Haebob, L. I., 

 December 7, 1908 



MUCOR CULTURES 



In the study of the Mucoraceae for several 

 years, some interesting facts concerning the 

 development or rather the non-development of 

 zygospores were observed. The experiments 

 were made with the common Mucor stolonifer 

 Ehrenberg. The media used were bread, 

 pumpkin, orange, commeal, decoction of horse 

 manure with gelatine, Pasteur's solution with 

 gelatine, Hamaker culture mediimi.* The 

 cultures were made with sterilized and un- 

 sterilized media. The spores for inoculation 

 were taken from plants grown in the labora- 

 tory, from specimens collected for the herbar- 

 ium, and from specimens sent to us by friends. 

 In one thousand cultures not one zygospore 

 was discovered. 



In addition to the cultures, five hundred 

 specimens of this species found growing 

 spontaneously in different places were also 

 examined but not one zygospore was observed. 



Besides these experiments, many cultures 

 were made and many specimens examined, a 

 record of the exact number of which, however, 



'Hamaker, Science, XXIII., 710, 1906. 



was not kept. It is a conservative estimate to 

 say that five hundred observations of this kind 

 were made. This makes a grand total of two 

 thousand observations without a single zygo- 

 spore. 



Experiments were also made to determine 

 the development of this Mucor under anaerobic 

 conditions. The media used for these experi- 

 ments were orange, bread and Hamaker cul- 

 ture medium. All were sterilized. In giving 

 the results of these experiments below, the 

 word commeal will be used for the Hamaker 

 medium. Cornmeal is the principal constitu- 

 ent of the medium. The material for inocula- 

 tion was kindly furnished by Dr. Niewland, 

 of Notre Dame University. 



Small wide-mouthed bottles were used for 

 the cultures. The medium was placed in 

 the bottles and the bottles then closed with 

 cotton and all sterilized. After inoculation, 

 the bottles were placed into Novi jars and the 

 jars filled with gas. The jars with the bottles 

 were then set aside for observation. The fol- 

 lowing results were obtained. 



In Hydrogen. — On orange, mycelium de- 

 veloped but few sporangiophores, no zygo- 

 spores; on bread, no development; on corn- 

 meal, no development. 



In Nitrogen. — On orange, mycelium and 

 few sporangiophores, no zygospores ; on bread, 

 about the same result; on cornmeal, about the 

 same result. 



In Carbon Dioxide. — On orange, mycelium 

 well developed but few sporangiophores; on 

 bread, mycelium profusely developed, many 

 sporangiophores, no sporangia, no zygospores; 

 on cornmeal, no development. 



It seems that the absence of oxygen is not 

 a necessary condition for the growth of zygo- 

 spores. 



David E. Sumstine 



University of Pittsbueg 



T3E BOTANICAL SOCIETY OF AMERICA 

 A UNION or the botanical societt op amebica, 



THE society fob PLANT MOEPHOLOQT AND 



PHYSIOLOGY AND THE AMERICAN 



MYCOLOGICAL SOCIETY 



The third annual meeting of the. federated 

 societies (the fifteenth of the Botanical Society 



