and Laboratory Methods. 1663 



Schaffner, J. H. A Contribution to the Life The flower in the deeply buried bulb 

 History and Cytology of Erythronium. Bot. begins to develop in early summer and 

 3 9-3 7, P !>• 4 9' 9 • l^y l-j^g ^j-gj. q£ October the archesporial 



cell in the nucellus and the pollen mother cells in the anther can be distin- 

 guished. By December first, the pollen mother cells have divided to form the 

 four microspores. The first division of the nucleus of the microspore takes place 

 sometime between December first and April first. The nucleus of the arche- 

 sporial cell in the nucellus does not divide until spring and, consequently, this 

 nucleus, in which the reduction of chromosomes takes place, has a period of 

 development extending over six, and sometimes even eight, months. The flow- 

 ers are growing rapidly before the frost is out of the ground. Ripe seed is 

 scarce, but the plant propagates very readily by bulbs. In mitoses in the bulb 

 the spindle is bipolar, first appearing as dome-shaped caps at opposite poles of 

 the nucleus, as described by the author for the root tips of Alliufn cepa. 



Pollen grains are well developed before the frost is out of the ground. The 

 tube nucleus stains slightly and is comparatively small, while the generative 

 nucleus is large and is surrounded by a densely staining mass of cytoplasm 

 which is organized into a cell of amoeboid form. 



In the nucleus of the megaspore the spirem takes the form of twelve loops 

 which break apart to form twelve chomosomes. The chomosomes present little 

 uniformity in size and also vary in shape, but it can usually be seen that they 

 are double. During metakinesis each chromosome breaks in the middle, thus 

 accomplishing a transverse or reducing division in Weissman's sense. The 

 writer, however, admits that his evidence in favor of a transverse division is not 

 conclusive, but insists that there is less evidence in favor of a longitudinal divis- 

 ion. Multipolar spindles are frequent, but are not regarded as a stage in the 

 development of the bipolar spindle. 



Prof. Schaffner is still an ardent champion of the centrosome in higher plants 

 and he attributes to it an essential role in the development of the spindle and 

 also of the radiations at the poles. After the first division the daughter nuclei 

 pass into the resting condition and in subsequent divisions the splitting of the 

 chromosomes is longitudinal. There is no row of macrospores, but the develop- 

 ment proceeds as in LiUic7fi^ TuHpa, and FritiUaria. 



Fertilization was not studied, but the development of the embryo was traced 

 in some detail. The figures create the impression that we are dealing with a 

 case of polyembryony, but only a single embryo is formed and the resemblance 

 to polyembryony is attributed to the behavior of the large suspensor, which is 

 highly developed as an absorbent organ. c. j. c. 



Lang, Wm. H. On Apospory in Anthoceros Although apospory has been known for 

 IcEvis. Ann. of Bot. IS: 503-510, pi. 27, some time in mosses and has been dis- 

 ^ covered in ferns, the present instance 



is the first to be recorded for liverworts. For the culture, young unopened 

 sporogonia of Anthoceros Icevis were cut into pieces about 5 mm. in length and 

 laid upon damp sand under a bell jar. After a month the pieces were more or 

 less decayed, but from the cut ends, and sometimes from the surfaces, small 

 green outgrowths could be detected. A study of sections showed that in nearly 

 all cases the outgrowths arise from single cells of the sporophyte and that their 

 development corresponds closely to the development of the gametophyte of Antho- 

 ceros from the spore. Abundant evidence was secured that the growths did not 

 come from spores in the sporogonium or from spores accidentally introduced 

 into the culture. The limited amount of material did not permit a study of the 

 attendant nuclear phenomena. c. j. c. 



