134 INTRODUCTION TO EMBRYOLOGY OF ANGIOSPERMS 



as in Lathraea, Lobelia, and Angelonia, have, however, to be in- 

 terpreted differently, for there is now no doubt that the cells in 

 question are really endosperm derivatives. The confusion was 

 caused by the fact that the micropylar cells of the endosperm some- 

 times show an appearance identical with that of the synergids — a 

 vacuole lying in the lower part of the cell and the nucleus and cyto- 

 plasm in the tapering upper part (see Rosen, 1947). In Myriophyl- 

 lum (Stolt, 1928; Soueges, 1940) and Hypecoum (Soueges, 1943) 

 even suspensor cells are known to show a surprising resemblance 

 to synergids. 



Antipodal Cells. Although usually short-lived, the antipodals 

 frequently show a considerable increase in size or number. In 

 some members of the Gentianaceae (Stolt, 1921) the three antipodal 

 cells divide to form about 10 to 12 cells (Fig. 87 D), and 

 in the Gramineae a still larger number of cells is produced (Fig. 

 87C). In Sasa paniculata (Yamaura, 1933), a member of the Bam- 

 busae, an many as 300 antipodal cells have been reported. 



In several genera of the Rubiaceae, like Putoria (Fagerlind, 1936a) 

 and Galium (Fagerlind, 1937), the basal antipodal cell is often 

 greatly elongated and acts as an aggressive haustorium (Fig. 87 

 B, E). In Phyllis (Fagerlind, 19366) all three of the antipodal cells 

 are swollen; the basal becomes 8-nucleate and each of the upper 

 two becomes 4-nucleate (Fig. 87 G,H). 



An increase in the number of antipodal cells and the number of 

 nuclei per antipodal cell is well known in the Compositae (Fig. 

 87 A, F). In Grindelia squarrosa, according to Howe (1926), only 

 two antipodal cells are formed, the one nearer the micropyle being 

 binucleate. One or both of these cells undergo further develop- 

 ment, growing laterally into the integument for a considerable dis- 

 tance. In Artemisia (Diettert, 1938) the number of antipodal cells 

 varies from three to six and each cell may have 2 or more nuclei. 

 The basal antipodal cell frequently elongates and penetrates 

 through the chalazal tissue, finally entering the ovarian chamber. 

 Rudbeckia bicolor (Maheshwari and Srinivasan, 1944), whose em- 

 bryo sac follows the Fritillaria type of development, has triploid 

 antipodal cells which attain a much larger size than the cells of the 

 egg apparatus (Fig. 88). The central antipodal cell, in particular, 

 persists for a long time, being recognizable even during embryonal 

 development. 



