92 



MORPHOLOGY OP ANGIOSPERMS 



synergids may not always divide. In the same category Casu- 

 arina, as reported by Treub, 25 has long been included ; but a 

 recent study of the genus by Frye U9 has shown that the usual 

 three micropylar nuclei occur. Fischer ° 

 reports the occurrence of two eggs in 

 Gomphrena, which Strasburger suggests 

 may have come from division of the nor- 



mal egg. 



In Loranthus and Casuarina Treub 

 also states that there are no antipoclals ; 

 but Frye's 119 recent investigation of the 

 latter form has resulted in the discovery 

 of three antipodals, which occur either 

 at the chalazal extremity of the expand- 

 ed portion of the sac, or in the tubular 

 haustorial elongation. 



In Helosis guayanensis ( Balanopho- 

 raceae) Chodat and Bernard S3 state that 

 the primary antipodal nucleus (binu- 

 cleate stage) rarely divides, but soon de- 

 generates, which means also the absence 

 of an antipodal polar nucleus (Fig. 40). 

 The same phenomenon has been ob- 

 served by Hall 1011 in Limnocharis, the 

 primary antipodal nucleus remaining 

 undivided. Several cases have also been 

 reported in which regularly formed po- 

 lar nuclei approach one another hut do 

 not fuse before endosperm formation, as 

 in Balanophora elongata (Treub 32 ), 

 confirmed also in B. indica by Van Tie- 

 ghem, 45 and in B. globosa by Lotsy 69 ; 

 but in the allied Rhopalocnemis (Lot- 

 sy 82 ) the polar nuclei fuse. In the or- 

 chid Gymnadenia also, Marshall- Ward " 

 slates that tlic polar nuclei do nut fuse; 

 in the parthenogenetic Antennaria alpina Juel 57 (Fie 41) ob- 

 served the same phenomenon ; in Lemna Caldwell " 2 reports that 

 the polar nuclei often do not fuse; and in Juglahs nigra Kar- 

 sten nr ' states that there is probably no fusion of polar nuclei, or 



Fia. 41. — Antennaria alpina. 

 Egg-cell much extended 

 and polar nuclei about to 

 divide; a, antipodal cell*; 

 «, Ggg ; p, polar nuclei ; s, 

 Bynergid; m, micropyle; 

 x 250. — After Juel." 



