46 
extraordinarily small dimension makes a spreading of the 
nuclei through the whole of the sac inevitable. There seems 
to be no reason why the formula C—I—®5 should not be used 
for these Podostemaceae. Dicraca elongata presents another con- 
dition. According to Macnus the mature sac consists of one 
synergid, the egg, and two antipodals. Only two or three of the 
earlier stages have been seen and a complete series could not 
be given. Under such circumstances it is difficult to decide about 
the formula. The two-nucleate stage is clearly polarised and vacu- 
olated, and the next division would suggest also C—IIla—3a. 
This however differs widely from the other Podostemaceae. 
The Penaeaceae as far as investigated (Stepaens 1908, 1909) 
show quite the same development as the Euphorbiaceae. The 
arrangement of the nuclei and the organisation of the vacuoles 
clearly shows a tetrasporic origin and suppression of all four 
chalazal groups, the formula thus being AAAA—Ia—5 (fig. 10, 
p- 43). The “micropylar“ character of the lateral and chalazal 
groups of cells is emphasized by the fact that embryos were 
seen arising from one of these groups. 
The Onagraceae, (Guerts 1909, Mopinewsk1 1909, Werner 1914, 
Renner 1914, Tickwoum 1914, 1915, Isnixawa 1918) show an 
absolute uniformity in their development. No need to describe 
the several stages in detail. The spreading of the protoplasm, 
the vacuolation, the direction of the spindles and the crowding 
of the four nuclei at the topend of the sac, these all make the 
total suppression of the chalazal group so evident that Geerts 
already said: “In der Oen. Lam. ist die erste Teilung im Em- 
bryosack ausgefallen, und es entstehen somit gar keine Anti- 
poden und kein unterer Polkern.« Form. A—I-- 5. He however 
did not recognise the individuality of the nuclei, for he still 
homologised the two-nucleate stage with the same stage in 
other Angiosperms, supposing the chalazal nucleus to be dis- 
placed by protosplasm-stream. 
Of several Gunnera species the life history of the female ga- 
metophyte is published. We can pass the first publication 
(Scunzcc, 1902) on the subject as his record could not be con- 
firmed by Ernsr (1908). All other publications, however, (Mop!- 
