ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 571 



a large cell which does not divide further, but finally disappears through 

 the encroachment of the endosperm. The upper daughter nucleus 

 travels back toward the egg-apparatus and by further division forms 

 the endosperm, which at an early stage consists of only a single layer 

 of granular protoplasm lining the sac, in which are imbedded free 

 nuclei, but later walls are formed although not easily distinguishable. 



Fertilisation occurs before the first division of the polar nucleus ; 

 actual fusion of sperm-cell and oosphere was not observed. The first 

 division of the egg is into suspensor and embryo-cell. The original 

 suspensor cell increases much in size but never divides except in cases 

 of polyembryony, when an embryogenic mass is formed from which 

 several embryos bud out somewhat as in Erythronium amtrieanum and 

 Tulipa Gcsneri. In the older embryo the suspensor consists in addition 

 of some of the cells derived from the first terminal segment, and may 

 comprise four to five cells. The first division of the embryo-cell is 

 always transverse, but the next may be vertical, transverse, or oblique. 

 When vertical or oblique the growing point of the stem and the coty- 

 ledon both arise from terminal segments, thus agreeing with Zannichcllia 

 but differing from Naias. The author concludes that there is no regular 

 order of division in the formation of the young embryo after the first 

 two walls are formed. In the older stages of the embryo the growing 

 point was apparently always of lateral origin. 



Structure of Achenes.* — E. Villari calls attention to the confusion 

 arising from the terms employed in systematic botany to denote various 

 kinds of fruits, one and the same term being used to include a diversity 

 of fruits which in their morphological origin have but little in common 

 with one another. In order to contribute towards a better classification, 

 he has studied the structure of the achenes of Anemone hortensis, Banun- 

 culus muricatus, Delphinium haltcratum, Daucus Carota, Senecio vulgaris, 

 Sonchus tenerrimw, S. oleraceus, Tolpis quadriaristata, Carthamus lana- 

 tus, Helianthus annuus, Bumex glomeratus, Mirabilis Jalapa, Oxybaphus 

 viscosus, and Parietaria lusitanica. He often found it impossible to make 

 out in the mature fruit the number of carpels of which it was composed. 

 At other times the sutures were quite apparent. He considers that not 

 only the number of the carpels, but also the superior or inferior position 

 of the ovaries, ought to be taken into account, and that epiachenes (in- 

 cluding periachenes) should be distinguished from hypoachenes. The 

 distinction of achene from caryopsis is of slight importance, as in 

 Urticacese, Nyctagineae, and Ranunculaceae, he has found achenes with 

 the pericarp more or less adherent to the seed. 



Germination in Piperaceae.-f— D. S. Johnson has studied the ger- 

 mination of the seeds of Peperomia pellucida. The bulk of the ripe seed 

 is made up of perisperm rich in starch ; a thin layer of endosperm sur- 

 rounds the globular embryo. The seed-coat is burst by increase in 

 size of embryo and endosperm. The endosperm pushes out of the seed 

 continuing to surround the embryo until the radicle and cotyledons are 

 well formed. The radicle and later the bases of the cotyledons push 

 out through the sac of the endosperm, which remains as a cap tightly 



* Malpiglna, xv. (1902) pp. 1SS-99. 



f Johns Hopkins Univ. Circulars, xxi. (1902) p. 86. 



