2530 Journal of Applied Microscopy 



tion of the chromosomes, appears as if filled with a homogeneous fluid in which 

 movable thread-like structures may appear between the separating groups of chro- 

 mosomes. Prof. Zacharias believes that his own investigations, as well as those 

 of morphologists, show that definite spindle fibers have not yet been demon- 

 strated in the living cell and that it is possible that the structures seen 

 in fixed material may be artifacts. c. j. c. 



Hegelmaier, F. Zur Kenntniss der Polyem- Prof. Hegelmaier's preliminary an- 



bryonie von Ettphorhia diilcis Jacq. iPnr- ^ r u u-x i i u 



purata Thuill.). Ber. d, deutsch. bot Gesell. nouncement of habitual polyembryony 

 21 : 6-19, p]. 2, 1903. in Euphorbia dulcis has already been 



noted in the Journal (p. 2058, Nov. 1902). In the present paper, which is 

 accompanied by figures, the previous observations are confirmed. The more 

 extended investigation shows that about three-fourths of the ovules contain more 

 than one embryo. A considerable percentage of the pollen is sterile and fertil- 

 ization was not observed, although it probably occurs in many cases. Pollination 

 is not necessary for the production of adventitious embryos, at least not for those 

 coming from the nucellus. Whether an embryo would develop from an ^g'g 

 without fertilization, was not determined. The writer withdraws his earlier 

 statement that polyembryony, as found in Euphorbia, might lead to apogamy and 

 even to parthenogenesis. c. j. c. 



Tischler, Q, Ueber eine merkwiirdige Wachs- Irregular mitoses in the pollen mother 



thumeischeinung in den Samenanlaeen von n j >.i. ^ c ^- c 



Cytisus AdamiVoxx. Ber. d. deutsch. bot. Cell and the consequent formation of 



Gesell. 21 : S2-89, pi. 5, 1903. imperfect pollen has already been noted 



in several sterile hybrids. In C)'//>//j'^(^A?;«/, a hybrid between Cytisus laburnum 



and C. purpureus, the development of the pollen is regular, but abnormalities 



which result in sterility are found in the ovule. After the integuments are quite 



well developed, a region at the base of the nucellus, rich in protoplasm, begins to 



grow with great rapidity, so that the nucellus is soon forced out through the 



micropyle. Often no megaspore mother-cell can be detected, sometimes a larger 



cell with shrunken protoplasm and a few nuclei indicates that a megaspore 



mother-cell had begun to germinate, and occasionally, when the nucellar growth 



is not particularly extensive, a normal embryo-sac may appear. c. j. c. 



Swingle, Deane B. Formation of the spores in Pure cultures were obtained and the 

 the sporangia of N/nzop„s nigncaMs and material was then fixed in various re- 



PhvcoDivces lutciis. U. b. Dept. of Agric, 



Bureau'of Plant Industry. Bulletin No. 37, agents. Particularly fine preparations 



pp. 1-40, pis. 1-6, 1903. ^gj.g obtained from material fixed for 



one hour in Flemming's fluid followed by twelve to twenty-four hours in Merkel's 



fluid or chrom-acetic acid. Sections were cut 'Ijx to 4// in thickness and were 



stained in the safranin, gentian-violet, orange combination. 



The paper deals especially with the mechanics of this peculiar cell division 

 found in these sporangia and with the nature and functions of the vacuole. It 

 is of interest to note that the four genera of the Mucorineae which have been 

 carefully investigated — Pilobolus and Sporodinia studied by Harper, and Rhizopus 

 and Phyconiyces studied by the present writer — differ considerably in the forma- 



