1893.) The Limitation of the term Spore. 133 
whether it be the pollen spore of the composite, the embryo- 
sac-spore of Casuarina or the less modified heterospore of 
Marsilia or Azolla or Isoetes, it becomes impossible to define 
€ spore without attention to the sexual potentiality of the 
cell and the function of its plant-product that is to be the re- 
sult of germination. Such spores as have undergone this pro- 
found morphological differentiation with regard to the sex of 
the plant to be produced from them may be given the name of 
quintos pores. 
To each of them the term 
y applied but, as I have attempted to show, 
y different implication in each case. The word 
Spore, then, in the Bacteriacex stands for a very different _ 
Structure than does the same word inthe Composite. It maybe 
objected that this is but to transfer new ideas into the word 
_ and thus make it more difficult to comprehend. The objection 
| Shardly wel taken, I think, for it is evident that the analysis 
| anything into the word that has not already, by 
‘ommon cons 
aS one passes hi 
een 
ee ae oo might be made that the propaga- 
' , € arc 
- tatives of as eg 
Marchantia or 7, 
“ould then either 
Sell. 
«the Sittada the view here indicated, that the persistence 
 Uuctive “Pore would be a fruitful study, may be pro- 
ells of 5 - Again, the notion that the vegeta- 
- Yettiog Porophytic st 
1M higher oe vegetative Propagation, so-called, that goes on 
being the ey tic structures. Vegetative development 
Ve yduited state of the cell it would be possible to ex- 
XVIII.—No, 4. 
