458 



SCIENCE. 



[N. S. Vol. XVII. No. 429. 



tively new field, illustrating the subject 

 fully by lantern slides. 



On the 'Blue' Color of Coniferous Timber: 

 Dr. Hermann von Schkenk, Missouri 

 Botanical Garden. 



Following an attack of the destructive 

 pine bark beetle in South Dakota, the sap- 

 wood of the bull pine {Pinus ponderosa) 

 turned blue. The color first appears at 

 the base of the tree some months after the 

 beetle attack, and gradually spreads up 

 the trunk until it has reached the top. 

 The color is evenly distributed throughout 

 the sapwood, and is very permanent. 

 Reference was made to the researches of 

 Vuillemin on the 'green' color of wood, 

 which he found due to a substance, xylin- 

 deine, formed by Helotium aeruginascens. 

 The 'blue' color of pine wood is due to the 

 growth in the wood of Ceratostoniella pi- 

 lifera, the fruiting bodies of which grow 

 on the outside of affected wood. The life 

 history of the fungus was described and 

 cultures exhibited. No coloring matter 

 could be extracted from 'blue' wood, and 

 it is probable that the color is largely due 

 to the blending of the brown color of the 

 fungus present throughout the 'blue' wood, 

 with the color of the wood itself. The 

 'blue' wood was shown to be as strong 

 mechanically as green wood. 



The Development of the Prothallium in 



Pinus: Dr. Margaret C. Ferguson, 



Wellesley College. 



A few of the more important conclusions 

 reached in a detailed study of the develop- 

 ment of the prothallium in Pinus were 

 given. 



The ovules are not differentiated in the 

 species of pines studied until about three 

 weeks before pollination. 



The maerospore-mother-eell may origin- 

 ate from a hypodermal cell as ordinarily 

 stated, but in a study of the development 



of the ovule there is not the slightest evi- 

 dence of such an origin. 



The first division of the macrospore- 

 mother-cell is heterotypical in nature and 

 gives rise to the one half number of 

 chromosomes. This division is quickly fol- 

 lowed either in the lower cell only, or in 

 both cells, by a homotypical division, thus 

 giving rise to axial rows of three or four 

 cells. The basal cell results from a true 

 tetrad-division, and always forms the func- 

 tional macr.ospore. 



The macrospore passes through a period 

 of growth lasting aboiit six weeks. Dur- 

 ing this time the peripheral layer of cyto- 

 plasm is organized and the nucleus takes 

 up a position in the wall-layer of cyto- 

 plasm near the micropylar end of the cell. 



Thirty-two free nuclei are formed be- 

 fore the approach of winter, and more than 

 two thousand nuclei have been counted at 

 the time when cell-walls are laid down. 

 In the later development of the prothal- 

 lium, true 'alveoli' are not formed, but 

 each cell divides several times before reach- 

 ing the center of the prothallial cavity. 



The 'spongy tissue' is not disintegrating 

 tissue, as previously stated, but it forms a 

 zone of physiological tissue which plays an 

 important part in the nutrition and sup- 

 port of the developing gametophyte. 



Fertilization in Taxodium: Professor W. 



G. CoKER, University of North Carolina. 



The male gametophyte of Taxodium is 

 much like that of the Cupressese. No 

 sterile prothallial cell is formed, and the 

 pollen-tube reaches the archegonia before 

 the division of the central cell occurs. 

 This division takes place simultaneously 

 with the ventral-canal division in the 

 archegonium, and in a day or two fertiliza- 

 tion is completed. The sperm-cells are of 

 equal size, and, as a rule, each is instru- 

 mental in fertilizing an archegonium. In 

 outline the sperm-cells resemble those of 



