ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 317 



found, consisting of an axis terminating in a conical receptacle, bear- 

 ing the two sets of organs, characteristic of what was formerly re- 

 garded as the female flowers, but which appear to be partially aborted 

 or immature. Surrounding the central receptacle is a whorl of several 

 pinnate leaves, with their upper parts folded in between the petioles of 

 the central gynoecium, and bearing rows of synangia similar to those of 

 the Marattiaceffi. No specimens have yet been seen in which l)oth the 

 androecium and gynoecium are mature. This may be explained by re- 

 garding it as a case of dichogamy, in which the male organs ripen 

 first, or as comparable to the male flowers of Welwitschia, in which 

 the female portion is functionless. 



Fertilisation and Embryogeny in Cephalotaxus Fortunei.* — W. C. 



Coker has investigated the fertilisation and embryogeny in Cepha- 

 lotaxus Fortunei, and finds that, as in other Conifers, the pollen-tube 

 contains two nuclei and a body-cell ; just before fertilisation the 

 latter divides into two sperm-cells of unequal size, the larger of 

 which alone is functional. This agrees with all the Taxacese except 

 Torreya californica, and it would seem that in all Gymnosperms whose 

 pollen-tubes fertilise only one archegonium, there is but one functional 

 sperm-nucleus. There are 3-5 archegonia, which are usually long and 

 pointed below, each with a poorly-developed jacket and 2-5 neck-cells. 

 The ventral canal nucleus has no protoplasm and gradually disappears. 

 Both sperm-cells are discharged into the egg, the larger nucleus sinks 

 into the egg-nucleus, and its protoplasm surrounds the fnsmg nuclei. 

 Cell-walls are first formed in the 16-cell stage, thus agreeing with 

 Taxus and Podocarpus, which are the only known Conifers in which 

 this phenomenon occurs. The pro-embryo terminates in two long cells, 

 which appear to have a secretive function ; it much resembles that of 

 Taxus. 



Development of Pollen in Nymphsea and Nuphar.f — W. Lubi- 

 menko and A. Maige have studied the variations of volume of the 

 nucleus, of the chromatic mass, and of the cell, in the course of de- 

 velopment of the pollen of NymphcBU alha and Nuphar luteum. In 

 the nucleus itself the relative masses of the chromatic mass have been 

 calculated by comparing the mean surfaces of the equatorial plates of 

 the three vegetative and pollen-forming divisions. The chief results 

 at present obtained are, that in the vegetative parenchyma of the anther, 



/N\ . 

 the ratio between the volume of the nucleus and that of the cell / ^ j is 



continually decreasing ; on the other hand, at no stage of development 

 of the pollen is there any absolute quantitative reduction of the chromatic 

 mass of the nucleus. 



Pollen-tube of Houstonia coerulea.J — C. A. Mathewson gives an 

 account of his investigations, and shows that the cells with which the 

 pollen-tube comes in contact have only a passive influence upon it, while 



* Bot. Gaz., xliii. (1907) pp. 1-10 (1 pi., 5 figs in text). 



t Comptes Reudus, cxliv. (1237) pp. 214-17 (1 fig.). 



X Bull. Torrey Bot. Club, xxxiii. (1906) pp. 487-93 (figs. 1-3). 



