582 



SCIENCE. 



[N. S. Vol. XII. No. 303. 



shape, to those of the fern rust Melamp- 

 sorella aspidiotus (Pk.) Mag., upon Onoclea 

 and other marsh ferns. 



A Mold Isolated from Tan-Bark Liquors : 



By Katharine L. Golden. 



A mold was isolated from tan-bark 

 liquors which were obtained from a tanning 

 factory employing the liming process for 

 unhairing the hides. The mold was pres- 

 ent in both fresh, sweet and sour liquors. 

 The mold is pink in color and has a char- 

 acteristic floury appearance, due to the 

 great number of spores formed. The or- 

 ganism fermented sucrose, dextrose and 

 maltose. In most gelatine it grew pro- 

 fusely, developing a pronounced pink color, 

 whereas in the ordinary meat gelatine the 

 development was scanty and pale. Three 

 distinct enzymes were developed by the ac- 

 tion of the mold ; a tryptic, a diastatic and 

 a rennet enzyme ; all three fairly active- 

 The protoplasm in some of the larger 

 hyphai was strongly motile, though the 

 hyphse seemed to be possessed of septa. 

 So far as could be determined by the aid of 

 stains and by salts causing osmotic activity 

 in the mold, the seeming septa are thick- 

 ened rings on the outside of the filaments. 

 The mold developed, in the various media 

 used, an odor resembling that of tanned 

 hides. No sexual organs were developed. 

 Photo-micrographs and diagrams were used 

 to show the appearance of the mold in the 

 various stages of development. 



The Embryo-sac of Peperomia pellucida : By 



Duncan S. Johnson. 



The primary archesporial cell of P. pellu- 

 cida is single and subepidermal. It cuts off 

 a single tapetal cell above and then im- 

 mediately develops to the embryo-sac. The 

 nucleus of the embryo-sac divides by mitosis 

 to sixteen similar nuclei, distributed about 

 in the peripheral layer of cytoplasm. Two 

 of these nuclei are soon found at the upper 

 end of the sac with a rather larger portion of 



cytoplasm about each. The larger of these 

 two nuclei with its cytoplasm forms the egg^ 

 the wall of which is at first very delicate 

 and indistinct. The other seems to play the 

 part of a synergid, and it also has no distinct 

 wall until a much later stage. Eight of the 

 remaining fourteen peripheral nuclei collect 

 in a compact group, located near the lateral 

 or basal wall of the embryo-sac, or often 

 just below the egg. Before the male and 

 female nuclei fuse these eight nuclei fuse 

 together completely into one large nucleus 

 which from this time behaves like the endo- 

 sperm nucleus of the ordinary Angiosperm 

 embryo-sac. This nucleus divides before 

 any change is visible in the egg. A cell 

 wall is formed immediately at each division, 

 from the cell plate of the spindle, so that in 

 the ripe seed there are forty or more endo- 

 sperm cells, completely surrounding the em- 

 bryo except above. The embryo at this 

 time consists of twenty or more cells and 

 reaches half way to the base of the embryo- 

 sac. The remaining six peripheral nuclei 

 are seen at this stage to be flattened against 

 the wall of the but little enlarged embryo- 

 sac by the endosperm cells and show signs 

 of degeneration. The endosperm cells ap- 

 pear at this time to have protoplasmic con- 

 tents only, but the whole tissue of the rel- 

 atively much enlarged nucellus is densely 

 packed with starch. The results here given 

 agree with those recently published by 

 Campbell, for this form up to the sixteen- 

 nucleate stage of the embryo-sac. But he 

 finds two synergidse and interprets the 

 group of eight nuclei as probably antipodals, 

 which he thinks separate again later. He 

 also apparently interprets as part of the 

 embryo the mass of endosperm cells which 

 finally fill most of the embryo-sac and there- 

 fore concludes that there is no endosperm. 



A Contribution to a Knowledge of the Organ- 

 ogeny of the Flower and of the Embryology of 

 the Gaprifoliacea : By Nellie P. Hewins. 



