ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 233 



changes, two integuments are being formed. The embryo-sac nucleus 

 divides twice, giving rise to four nuclei, which lie in pairs at each pole 

 of the cell. The two at the micropylar end again divide, but those 

 at the chalazal end usually remain undivided, and form, together with 

 the other four, the six nuclei of the embryo-sac. Three of the micro- 

 pylar nuclei form the synergid^e and oosphere, while the fourth passes to 

 the centre and fuses with one of the nuclei from the chalazal end to 

 form the secondary nucleus ; the remaining nucleus (or nuclei rarely) 

 at the chalazal end forms a simple antipodal nucleus. Of the two 

 male-cells which enter the embryo-sac, one fuses with the oosphere and 

 the other with the secondary nucleus. As a result of fertilization, the 

 oosphere immediately enlarges, and develops into the embryo, while the 

 fertilized secondary nucleus perishes without forming any albumen 

 (endosperm). 



In Serapias the first stages of development are practically identical 

 with those described above, but whereas in Spiranthes the embryo-sac 

 is sometimes found to have eight nuclei, in Serapias the number is 

 invariably six. The polar nuclei also have a more interesting develop- 

 ment ; sometimes they come into contact without fusing, while at other 

 times the upper polar nucleus travels down to meet the lower one, and 

 remains in contact both with the latter and with the antipodal. When 

 the second male-cell enters the embryo-sac it passes towards the polar 

 nuclei, and ultimately the group fuses, although it is not rare to find 

 groups where fusion never occurs. In either case they soon perish, with- 

 out having formed any endosperm. The author concludes that the 

 typical Orchid had originally four macrospores, but that the four may 

 be reduced to three in the manner described above ; corresponding with 

 this condition, the embryo-sac of the type contains eight nuclei, but the 

 simpler and more recent type contains only six. In Spiranthes australis 

 an intermediate stage is seen, since the embryo-sac has sometimes 

 eight, but at other times six nuclei. 



In the greater number of the Orchidaceae the formation of the 

 secondary nucleus is of great interest. It is usually formed by the fusion 

 of the two polar nuclei and one male-cell. In Cypripediiim it results 

 from the fusion of a synergid, a polar nucleus, and a male-cell. In those 

 species which have six nuclei in the embryo-sac it frequently results from 

 the fusion of two polar nuclei, an antipodal and a male-cell. Usually 

 no endosperm is formed, but in Cypripedium four daughter-nuclei are 

 formed and then disintegrate. The suspensor varies from a series of two 

 dozen cells to a considerably reduced series, or it may even be represented 

 by a single cell. 



Structure of Pepper.* — T. E. Wallis publishes a description of 

 some hitherto unnoticed tissues which occur in the berry of white pepper, 

 and which when crushed give the appearance of adulteration in pure 

 samples. At the apex of the berry is a conical depression resting 

 immediately upon the cavity containing the embryo and endosperm. 

 In this region the pericarp is modified. The sclerenchyma is more 



* Analyst, May, 1915, pp. 1-8 (5 figs.). 

 April 18th, 1917 R 



