130 MORPHOLOGY OF SPERMATOPHYTES 



minal pore. Each male cell fuses with a free egg, and as many 

 oospores are formed as there are male cells discharged into the 

 sac that is, twice as many as there are discharging pollen 

 tubes (Fig. 91, /). The oospore was observed to organize at 

 once about the fusion nucleus a comparatively dense layer of 

 cytoplasm, and soon a cell membrane appeared. The oospores 

 may remain free, or they may become attached to the tips of the 

 pollen tubes which belong to them. 



IV. THE EMBRYO 



Ephedra. An account of the development of the embryo of 

 Ephedra aUissima. is given by Strasburger. 3 Germination be- 

 gins with free nuclear division, and two to eight free cells, some- 

 times more, are organized within the oospore (Fig. 89, B). 

 These free cells do not organize any definite tissue as in Coni- 

 fers. As a consequence, each cell continues to act independ- 

 ently, elongating to form a suspensorlike tube, which emerges 

 from the oospore and penetrates the endosperm (Fig. 89, C). 

 The more or less numerous tubes, emerging in various direc- 

 tions, are bulbous within the oospore, where they are in contact 

 with its nutritive supply, and at the free tip cut off a single cell, 

 from which the embryo proper is developed. The embryonal 

 cell divides transversely, which is followed by other transverse 

 divisions, forming a short filament (Fig. 89, D, E}. Longitudinal 

 divisions succeed, and later periclinal divisions (Fig. 89, F).- No 

 details of the organization of the growing points are recorded. 



Tumboa. After fertilization, it is reported that the arche- 

 gonium initial elongates and penetrates the endosperm as a 

 suspensor, which is a long, much-coiled, and very persistent 

 structure, and carries the egg in its tip. It is probably the fact 

 that the so-called archegonial suspensor is a tube developed by 

 the oospore, just as in the free oospores of Gnetum, and that the 

 so-called egg in its tip is the nucleus of the oospore. In any 

 event, the embryonal cell appears as a small cell cut off at the 

 tip of the suspensorlike tube (Fig. 90), and gives rise not only to 

 the embryo proper but also to numerous embryonal tubes 

 (Fig. 92). ^ 



According to Bower's account 6j 7 of the embryo, the first 

 division of the embryonal cell is longitudinal. Then a trans- 



