158 INTRODUCTION TO EMBRYOLOGY OF ANG10SPERMS 



Goebel (1933) thought that in the angiosperms the generative 

 cell is always cut off on the distal (i.e., ventral) side of the micro- 

 spore. Geitler (1935) showed, however, that there is no such uni- 

 formity and that the generative cell may be cut off either on the 

 outer side (Fig. 97 J, L), or on the inner side (Fig. 97 K, 98), or on a 

 radial wall (Fig. 97 A-I), or in a corner instead of the middle of the 

 radial wall. To cite a few examples, the first-named condition has 



Fig. 98. Microsporogenesis and development of male gametophyte in Juncus 

 filiformis (A-F) and J. squarrosus (G-I). A, interkinesis after Meiosis I, showing 

 formation of ephemeral cell plate. B, microspore nuclei. C, microspore nuclei 

 in prophase; note intervening plasma membranes. D, microspore nuclei in ana- 

 phase. E, F, formation of vegetative and generative cells. G, one member of 

 tetrad, showing generative cell in late anaphase. H, same, division nearly com- 

 pleted. 7, older stage, showing vegetative nucleus and two sperm cells. (After 

 Wulff, 1939a.) 



been reported in Elodea (Wylie, 1904), Vaccinium (Samuelsson' 

 1913), Albizzia (Maheshwari, 1931), Acacia (Newman, 1934), 

 Asimina (Locke, 1936), and most members of the Orchidaceae 

 (Swamy, 1949); the second in Symplocarpus (Duggar, 1900), Xyris 

 (Weinzieher, 1914), Erica (Geitler, 1935), Juncus (Wulff, 1939a), 

 Cyanastrum (Nietsch, 1941), and most members of the Cyperaceae 

 (Piech, 1928); the third in Allium (Geitler, 1935); and the fourth 



