210 



SCIENCE. 



[N. S. Vol. XXII. No. 555. 



abortive. The plant is largely confined within 

 the spore. The protruding portion may de- 

 velop more or less chlorophyll and, conse- 

 quently, is not completely dependent. 



sporal and the resulting plant is entirely para- 

 sitic. Further, the spore, with its contained 

 plant, is never shed from the enclosing struc- 

 tures. At the beginning of germination there 



C.Pinus, 



D. Gnetum Gnemon. 



E. Gnetum ^p. 



EPeperomia. 



G.MosUnjIospems. 



H. Cijpripedm(ra^. 



L 



HmM'm. 



Fig. 2. 



The gymnosperms (Fig. 2, C) are hetero- 

 sporous and, as a rule, only one of the mega- 

 spores germinates, the other three becoming 

 abortive.^ The germination is entirely intra- 



^ The three abortive megaspores are represented 

 in C — H of the diagram by three heavy lines, 



is a prolonged period of free nuclear division, 

 but later, cell walls are formed and at the 

 stage shown in the diagram the plant consists 

 of a solid cellular tissue. 



although they disappear completely before the 

 stage shown in the diagrams has been reached. 



